diff --git a/system/orm.php b/system/orm.php
index ed3d28ba..2389efc0 100644
--- a/system/orm.php
+++ b/system/orm.php
@@ -1,2281 +1,2365 @@
 <?php
 
-/**
- *
- * Idiorm
- *
- * http://github.com/j4mie/idiorm/
- *
- * A single-class super-simple database abstraction layer for PHP.
- * Provides (nearly) zero-configuration object-relational mapping
- * and a fluent interface for building basic, commonly-used queries.
- *
- * BSD Licensed.
- *
- * Copyright (c) 2010, Jamie Matthews
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * * Redistributions of source code must retain the above copyright notice, this
- *   list of conditions and the following disclaimer.
- *
- * * Redistributions in binary form must reproduce the above copyright notice,
- *   this list of conditions and the following disclaimer in the documentation
- *   and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-class ORM implements ArrayAccess {
-
-    // ----------------------- //
-    // --- CLASS CONSTANTS --- //
-    // ----------------------- //
-
-    // WHERE and HAVING condition array keys
-    const CONDITION_FRAGMENT = 0;
-    const CONDITION_VALUES = 1;
-
-    const DEFAULT_CONNECTION = 'default';
-
-    // Limit clause style
-    const LIMIT_STYLE_TOP_N = "top";
-    const LIMIT_STYLE_LIMIT = "limit";
-
-    // ------------------------ //
-    // --- CLASS PROPERTIES --- //
-    // ------------------------ //
-
-    // Class configuration
-    protected static $_default_config = array(
-        'connection_string' => 'sqlite::memory:',
-        'id_column' => 'id',
-        'id_column_overrides' => array(),
-        'error_mode' => PDO::ERRMODE_EXCEPTION,
-        'username' => null,
-        'password' => null,
-        'driver_options' => null,
-        'identifier_quote_character' => null, // if this is null, will be autodetected
-        'limit_clause_style' => null, // if this is null, will be autodetected
-        'logging' => false,
-        'logger' => null,
-        'caching' => false,
-        'caching_auto_clear' => false,
-        'return_result_sets' => false,
-    );
-
-    // Map of configuration settings
-    protected static $_config = array();
-
-    // Map of database connections, instances of the PDO class
-    protected static $_db = array();
-
-    // Last query run, only populated if logging is enabled
-    protected static $_last_query;
-
-    // Log of all queries run, mapped by connection key, only populated if logging is enabled
-    protected static $_query_log = array();
-
-    // Query cache, only used if query caching is enabled
-    protected static $_query_cache = array();
-
-    // Reference to previously used PDOStatement object to enable low-level access, if needed
-    protected static $_last_statement = null;
-
-    // --------------------------- //
-    // --- INSTANCE PROPERTIES --- //
-    // --------------------------- //
-
-    // Key name of the connections in self::$_db used by this instance
-    protected $_connection_name;
-
-    // The name of the table the current ORM instance is associated with
-    protected $_table_name;
-
-    // Alias for the table to be used in SELECT queries
-    protected $_table_alias = null;
-
-    // Values to be bound to the query
-    protected $_values = array();
-
-    // Columns to select in the result
-    protected $_result_columns = array('*');
-
-    // Are we using the default result column or have these been manually changed?
-    protected $_using_default_result_columns = true;
-
-    // Join sources
-    protected $_join_sources = array();
-
-    // Should the query include a DISTINCT keyword?
-    protected $_distinct = false;
-
-    // Is this a raw query?
-    protected $_is_raw_query = false;
-
-    // The raw query
-    protected $_raw_query = '';
-
-    // The raw query parameters
-    protected $_raw_parameters = array();
-
-    // Array of WHERE clauses
-    protected $_where_conditions = array();
-
-    // LIMIT
-    protected $_limit = null;
-
-    // OFFSET
-    protected $_offset = null;
-
-    // ORDER BY
-    protected $_order_by = array();
-
-    // GROUP BY
-    protected $_group_by = array();
-
-    // HAVING
-    protected $_having_conditions = array();
-
-    // The data for a hydrated instance of the class
-    protected $_data = array();
-
-    // Fields that have been modified during the
-    // lifetime of the object
-    protected $_dirty_fields = array();
-
-    // Fields that are to be inserted in the DB raw
-    protected $_expr_fields = array();
-
-    // Is this a new object (has create() been called)?
-    protected $_is_new = false;
-
-    // Name of the column to use as the primary key for
-    // this instance only. Overrides the config settings.
-    protected $_instance_id_column = null;
-
-    // ---------------------- //
-    // --- STATIC METHODS --- //
-    // ---------------------- //
-
     /**
-     * Pass configuration settings to the class in the form of
-     * key/value pairs. As a shortcut, if the second argument
-     * is omitted and the key is a string, the setting is
-     * assumed to be the DSN string used by PDO to connect
-     * to the database (often, this will be the only configuration
-     * required to use Idiorm). If you have more than one setting
-     * you wish to configure, another shortcut is to pass an array
-     * of settings (and omit the second argument).
-     * @param string $key
-     * @param mixed $value
-     * @param string $connection_name Which connection to use
-     */
-    public static function configure($key, $value = null, $connection_name = self::DEFAULT_CONNECTION) {
-        self::_setup_db_config($connection_name); //ensures at least default config is set
-
-        if (is_array($key)) {
-            // Shortcut: If only one array argument is passed,
-            // assume it's an array of configuration settings
-            foreach ($key as $conf_key => $conf_value) {
-                self::configure($conf_key, $conf_value, $connection_name);
-            }
-        } else {
-            if (is_null($value)) {
-                // Shortcut: If only one string argument is passed,
-                // assume it's a connection string
-                $value = $key;
-                $key = 'connection_string';
-            }
-            self::$_config[$connection_name][$key] = $value;
-        }
-    }
-
-    /**
-     * Retrieve configuration options by key, or as whole array.
-     * @param string $key
-     * @param string $connection_name Which connection to use
-     */
-    public static function get_config($key = null, $connection_name = self::DEFAULT_CONNECTION) {
-        if ($key) {
-            return self::$_config[$connection_name][$key];
-        } else {
-            return self::$_config[$connection_name];
-        }
-    }
-
-    /**
-     * Delete all configs in _config array.
-     */
-    public static function reset_config() {
-        self::$_config = array();
-    }
-
-    /**
-     * Despite its slightly odd name, this is actually the factory
-     * method used to acquire instances of the class. It is named
-     * this way for the sake of a readable interface, ie
-     * ORM::for_table('table_name')->find_one()-> etc. As such,
-     * this will normally be the first method called in a chain.
-     * @param string $table_name
-     * @param string $connection_name Which connection to use
-     * @return ORM
-     */
-    public static function for_table($table_name, $connection_name = self::DEFAULT_CONNECTION) {
-        self::_setup_db($connection_name);
-        return new self($table_name, array(), $connection_name);
-    }
-
-
-    public static function execute($query) {
-        self::_setup_db(self::DEFAULT_CONNECTION);
-        return self::_execute($query);
-    }
-
-    /**
-     * Set up the database connection used by the class
-     * @param string $connection_name Which connection to use
-     */
-    protected static function _setup_db($connection_name = self::DEFAULT_CONNECTION) {
-        if (!array_key_exists($connection_name, self::$_db) ||
-            !is_object(self::$_db[$connection_name])) {
-            self::_setup_db_config($connection_name);
-
-            $db = new PDO(
-                self::$_config[$connection_name]['connection_string'],
-                self::$_config[$connection_name]['username'],
-                self::$_config[$connection_name]['password'],
-                self::$_config[$connection_name]['driver_options']
-            );
-
-            $db->setAttribute(PDO::ATTR_ERRMODE, self::$_config[$connection_name]['error_mode']);
-            self::set_db($db, $connection_name);
-        }
-    }
-
-    /**
-     * Ensures configuration (multiple connections) is at least set to default.
-     * @param string $connection_name Which connection to use
-     */
-    protected static function _setup_db_config($connection_name) {
-        if (!array_key_exists($connection_name, self::$_config)) {
-            self::$_config[$connection_name] = self::$_default_config;
-        }
-    }
-
-    /**
-     * Set the PDO object used by Idiorm to communicate with the database.
-     * This is public in case the ORM should use a ready-instantiated
-     * PDO object as its database connection. Accepts an optional string key
-     * to identify the connection if multiple connections are used.
-     * @param PDO $db
-     * @param string $connection_name Which connection to use
-     */
-    public static function set_db($db, $connection_name = self::DEFAULT_CONNECTION) {
-        self::_setup_db_config($connection_name);
-        self::$_db[$connection_name] = $db;
-        if(!is_null(self::$_db[$connection_name])) {
-            self::_setup_identifier_quote_character($connection_name);
-            self::_setup_limit_clause_style($connection_name);
-        }
-    }
-
-    /**
-     * Delete all registered PDO objects in _db array.
-     */
-    public static function reset_db() {
-        self::$_db = array();
-    }
-
-    /**
-     * Detect and initialise the character used to quote identifiers
-     * (table names, column names etc). If this has been specified
-     * manually using ORM::configure('identifier_quote_character', 'some-char'),
-     * this will do nothing.
-     * @param string $connection_name Which connection to use
-     */
-    protected static function _setup_identifier_quote_character($connection_name) {
-        if (is_null(self::$_config[$connection_name]['identifier_quote_character'])) {
-            self::$_config[$connection_name]['identifier_quote_character'] =
-                self::_detect_identifier_quote_character($connection_name);
-        }
-    }
-
-    /**
-     * Detect and initialise the limit clause style ("SELECT TOP 5" /
-     * "... LIMIT 5"). If this has been specified manually using
-     * ORM::configure('limit_clause_style', 'top'), this will do nothing.
-     * @param string $connection_name Which connection to use
-     */
-    public static function _setup_limit_clause_style($connection_name) {
-        if (is_null(self::$_config[$connection_name]['limit_clause_style'])) {
-            self::$_config[$connection_name]['limit_clause_style'] =
-                self::_detect_limit_clause_style($connection_name);
-        }
-    }
-
-    /**
-     * Return the correct character used to quote identifiers (table
-     * names, column names etc) by looking at the driver being used by PDO.
-     * @param string $connection_name Which connection to use
-     * @return string
-     */
-    protected static function _detect_identifier_quote_character($connection_name) {
-        switch(self::get_db($connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME)) {
-            case 'pgsql':
-            case 'sqlsrv':
-            case 'dblib':
-            case 'mssql':
-            case 'sybase':
-            case 'firebird':
-                return '"';
-            case 'mysql':
-            case 'sqlite':
-            case 'sqlite2':
-            default:
-                return '`';
-        }
-    }
-
-    /**
-     * Returns a constant after determining the appropriate limit clause
-     * style
-     * @param string $connection_name Which connection to use
-     * @return string Limit clause style keyword/constant
-     */
-    protected static function _detect_limit_clause_style($connection_name) {
-        switch(self::get_db($connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME)) {
-            case 'sqlsrv':
-            case 'dblib':
-            case 'mssql':
-                return ORM::LIMIT_STYLE_TOP_N;
-            default:
-                return ORM::LIMIT_STYLE_LIMIT;
-        }
-    }
-
-    /**
-     * Returns the PDO instance used by the the ORM to communicate with
-     * the database. This can be called if any low-level DB access is
-     * required outside the class. If multiple connections are used,
-     * accepts an optional key name for the connection.
-     * @param string $connection_name Which connection to use
-     * @return PDO
-     */
-    public static function get_db($connection_name = self::DEFAULT_CONNECTION) {
-        self::_setup_db($connection_name); // required in case this is called before Idiorm is instantiated
-        return self::$_db[$connection_name];
-    }
-
-    /**
-     * Executes a raw query as a wrapper for PDOStatement::execute.
-     * Useful for queries that can't be accomplished through Idiorm,
-     * particularly those using engine-specific features.
-     * @example raw_execute('SELECT `name`, AVG(`order`) FROM `customer` GROUP BY `name` HAVING AVG(`order`) > 10')
-     * @example raw_execute('INSERT OR REPLACE INTO `widget` (`id`, `name`) SELECT `id`, `name` FROM `other_table`')
-     * @param string $query The raw SQL query
-     * @param array  $parameters Optional bound parameters
-     * @param string $connection_name Which connection to use
-     * @return bool Success
-     */
-    public static function raw_execute($query, $parameters = array(), $connection_name = self::DEFAULT_CONNECTION) {
-        self::_setup_db($connection_name);
-        return self::_execute($query, $parameters, $connection_name);
-    }
-
-    /**
-     * Returns the PDOStatement instance last used by any connection wrapped by the ORM.
-     * Useful for access to PDOStatement::rowCount() or error information
-     * @return PDOStatement
-     */
-    public static function get_last_statement() {
-        return self::$_last_statement;
-    }
-
-    /**
-     * Internal helper method for executing statments. Logs queries, and
-     * stores statement object in ::_last_statment, accessible publicly
-     * through ::get_last_statement()
-     * @param string $query
-     * @param array $parameters An array of parameters to be bound in to the query
-     * @param string $connection_name Which connection to use
-     * @return bool Response of PDOStatement::execute()
-     */
-    protected static function _execute($query, $parameters = array(), $connection_name = self::DEFAULT_CONNECTION) {
-        $statement = self::get_db($connection_name)->prepare($query);
-        self::$_last_statement = $statement;
-        $time = microtime(true);
-
-        foreach ($parameters as $key => &$param) {
-            if (is_null($param)) {
-                $type = PDO::PARAM_NULL;
-            } else if (is_bool($param)) {
-                $type = PDO::PARAM_BOOL;
-            } else if (is_int($param)) {
-                $type = PDO::PARAM_INT;
-            } else {
-                $type = PDO::PARAM_STR;
-            }
-
-            $statement->bindParam(is_int($key) ? ++$key : $key, $param, $type);
-        }
-
-        $q = $statement->execute();
-        self::_log_query($query, $parameters, $connection_name, (microtime(true)-$time));
-
-        return $q;
-    }
-
-    /**
-     * Add a query to the internal query log. Only works if the
-     * 'logging' config option is set to true.
      *
-     * This works by manually binding the parameters to the query - the
-     * query isn't executed like this (PDO normally passes the query and
-     * parameters to the database which takes care of the binding) but
-     * doing it this way makes the logged queries more readable.
-     * @param string $query
-     * @param array $parameters An array of parameters to be bound in to the query
-     * @param string $connection_name Which connection to use
-     * @param float $query_time Query time
-     * @return bool
+     * Idiorm
+     *
+     * http://github.com/j4mie/idiorm/
+     *
+     * A single-class super-simple database abstraction layer for PHP.
+     * Provides (nearly) zero-configuration object-relational mapping
+     * and a fluent interface for building basic, commonly-used queries.
+     *
+     * BSD Licensed.
+     *
+     * Copyright (c) 2010, Jamie Matthews
+     * All rights reserved.
+     *
+     * Redistribution and use in source and binary forms, with or without
+     * modification, are permitted provided that the following conditions are met:
+     *
+     * * Redistributions of source code must retain the above copyright notice, this
+     *   list of conditions and the following disclaimer.
+     *
+     * * Redistributions in binary form must reproduce the above copyright notice,
+     *   this list of conditions and the following disclaimer in the documentation
+     *   and/or other materials provided with the distribution.
+     *
+     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+     * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+     * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+     * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+     * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+     *
+     *
+     * The methods documented below are magic methods that conform to PSR-1.
+     * This documentation exposes these methods to doc generators and IDEs.
+     * @see http://www.php-fig.org/psr/psr-1/
+     *
+     * @method static array|string getConfig($key = null, $connection_name = self::DEFAULT_CONNECTION)
+     * @method static null resetConfig()
+     * @method static \ORM forTable($table_name, $connection_name = self::DEFAULT_CONNECTION)
+     * @method static null setDb($db, $connection_name = self::DEFAULT_CONNECTION)
+     * @method static null resetDb()
+     * @method static null setupLimitClauseStyle($connection_name)
+     * @method static \PDO getDb($connection_name = self::DEFAULT_CONNECTION)
+     * @method static bool rawExecute($query, $parameters = array())
+     * @method static \PDOStatement getLastStatement()
+     * @method static string getLastQuery($connection_name = null)
+     * @method static array getQueryLog($connection_name = self::DEFAULT_CONNECTION)
+     * @method array getConnectionNames()
+     * @method $this useIdColumn($id_column)
+     * @method \ORM|bool findOne($id=null)
+     * @method array|\IdiormResultSet findMany()
+     * @method \IdiormResultSet findResultSet()
+     * @method array findArray()
+     * @method $this forceAllDirty()
+     * @method $this rawQuery($query, $parameters = array())
+     * @method $this tableAlias($alias)
+     * @method int countNullIdColumns()
+     * @method $this selectExpr($expr, $alias=null)
+     * @method \ORM selectMany($values)
+     * @method \ORM selectManyExpr($values)
+     * @method $this rawJoin($table, $constraint, $table_alias, $parameters = array())
+     * @method $this innerJoin($table, $constraint, $table_alias=null)
+     * @method $this leftOuterJoin($table, $constraint, $table_alias=null)
+     * @method $this rightOuterJoin($table, $constraint, $table_alias=null)
+     * @method $this fullOuterJoin($table, $constraint, $table_alias=null)
+     * @method $this whereEqual($column_name, $value=null)
+     * @method $this whereNotEqual($column_name, $value=null)
+     * @method $this whereIdIs($id)
+     * @method $this whereAnyIs($values, $operator='=')
+     * @method array|string whereIdIn($ids)
+     * @method $this whereLike($column_name, $value=null)
+     * @method $this whereNotLike($column_name, $value=null)
+     * @method $this whereGt($column_name, $value=null)
+     * @method $this whereLt($column_name, $value=null)
+     * @method $this whereGte($column_name, $value=null)
+     * @method $this whereLte($column_name, $value=null)
+     * @method $this whereIn($column_name, $values)
+     * @method $this whereNotIn($column_name, $values)
+     * @method $this whereNull($column_name)
+     * @method $this whereNotNull($column_name)
+     * @method $this whereRaw($clause, $parameters=array())
+     * @method $this orderByDesc($column_name)
+     * @method $this orderByAsc($column_name)
+     * @method $this orderByExpr($clause)
+     * @method $this groupBy($column_name)
+     * @method $this groupByExpr($expr)
+     * @method $this havingEqual($column_name, $value=null)
+     * @method $this havingNotEqual($column_name, $value=null)
+     * @method $this havingIdIs($id)
+     * @method $this havingLike($column_name, $value=null)
+     * @method $this havingNotLike($column_name, $value=null)
+     * @method $this havingGt($column_name, $value=null)
+     * @method $this havingLt($column_name, $value=null)
+     * @method $this havingGte($column_name, $value=null)
+     * @method $this havingLte($column_name, $value=null)
+     * @method $this havingIn($column_name, $values=null)
+     * @method $this havingNotIn($column_name, $values=null)
+     * @method $this havingNull($column_name)
+     * @method $this havingNotNull($column_name)
+     * @method $this havingRaw($clause, $parameters=array())
+     * @method static this clearCache($table_name = null, $connection_name = self::DEFAULT_CONNECTION)
+     * @method array asArray()
+     * @method bool setExpr($key, $value = null)
+     * @method bool isDirty($key)
+     * @method bool isNew()
      */
-    protected static function _log_query($query, $parameters, $connection_name, $query_time) {
-        // If logging is not enabled, do nothing
-        if (!self::$_config[$connection_name]['logging']) {
-            return false;
-        }
 
-        if (!isset(self::$_query_log[$connection_name])) {
-            self::$_query_log[$connection_name] = array();
-        }
+    class ORM implements ArrayAccess {
 
-        // Strip out any non-integer indexes from the parameters
-        foreach($parameters as $key => $value) {
-            if (!is_int($key)) unset($parameters[$key]);
-        }
+        // ----------------------- //
+        // --- CLASS CONSTANTS --- //
+        // ----------------------- //
 
-        if (count($parameters) > 0) {
-            // Escape the parameters
-            $parameters = array_map(array(self::get_db($connection_name), 'quote'), $parameters);
+        // WHERE and HAVING condition array keys
+        const CONDITION_FRAGMENT = 0;
+        const CONDITION_VALUES = 1;
 
-            // Avoid %format collision for vsprintf
-            $query = str_replace("%", "%%", $query);
+        const DEFAULT_CONNECTION = 'default';
 
-            // Replace placeholders in the query for vsprintf
-            if(false !== strpos($query, "'") || false !== strpos($query, '"')) {
-                $query = IdiormString::str_replace_outside_quotes("?", "%s", $query);
+        // Limit clause style
+        const LIMIT_STYLE_TOP_N = "top";
+        const LIMIT_STYLE_LIMIT = "limit";
+
+        // ------------------------ //
+        // --- CLASS PROPERTIES --- //
+        // ------------------------ //
+
+        // Class configuration
+        protected static $_default_config = array(
+            'connection_string' => 'sqlite::memory:',
+            'id_column' => 'id',
+            'id_column_overrides' => array(),
+            'error_mode' => PDO::ERRMODE_EXCEPTION,
+            'username' => null,
+            'password' => null,
+            'driver_options' => null,
+            'identifier_quote_character' => null, // if this is null, will be autodetected
+            'limit_clause_style' => null, // if this is null, will be autodetected
+            'logging' => false,
+            'logger' => null,
+            'caching' => false,
+            'caching_auto_clear' => false,
+            'return_result_sets' => false,
+        );
+
+        // Map of configuration settings
+        protected static $_config = array();
+
+        // Map of database connections, instances of the PDO class
+        protected static $_db = array();
+
+        // Last query run, only populated if logging is enabled
+        protected static $_last_query;
+
+        // Log of all queries run, mapped by connection key, only populated if logging is enabled
+        protected static $_query_log = array();
+
+        // Query cache, only used if query caching is enabled
+        protected static $_query_cache = array();
+
+        // Reference to previously used PDOStatement object to enable low-level access, if needed
+        protected static $_last_statement = null;
+
+        // --------------------------- //
+        // --- INSTANCE PROPERTIES --- //
+        // --------------------------- //
+
+        // Key name of the connections in self::$_db used by this instance
+        protected $_connection_name;
+
+        // The name of the table the current ORM instance is associated with
+        protected $_table_name;
+
+        // Alias for the table to be used in SELECT queries
+        protected $_table_alias = null;
+
+        // Values to be bound to the query
+        protected $_values = array();
+
+        // Columns to select in the result
+        protected $_result_columns = array('*');
+
+        // Are we using the default result column or have these been manually changed?
+        protected $_using_default_result_columns = true;
+
+        // Join sources
+        protected $_join_sources = array();
+
+        // Should the query include a DISTINCT keyword?
+        protected $_distinct = false;
+
+        // Is this a raw query?
+        protected $_is_raw_query = false;
+
+        // The raw query
+        protected $_raw_query = '';
+
+        // The raw query parameters
+        protected $_raw_parameters = array();
+
+        // Array of WHERE clauses
+        protected $_where_conditions = array();
+
+        // LIMIT
+        protected $_limit = null;
+
+        // OFFSET
+        protected $_offset = null;
+
+        // ORDER BY
+        protected $_order_by = array();
+
+        // GROUP BY
+        protected $_group_by = array();
+
+        // HAVING
+        protected $_having_conditions = array();
+
+        // The data for a hydrated instance of the class
+        protected $_data = array();
+
+        // Fields that have been modified during the
+        // lifetime of the object
+        protected $_dirty_fields = array();
+
+        // Fields that are to be inserted in the DB raw
+        protected $_expr_fields = array();
+
+        // Is this a new object (has create() been called)?
+        protected $_is_new = false;
+
+        // Name of the column to use as the primary key for
+        // this instance only. Overrides the config settings.
+        protected $_instance_id_column = null;
+
+        // ---------------------- //
+        // --- STATIC METHODS --- //
+        // ---------------------- //
+
+        /**
+         * Pass configuration settings to the class in the form of
+         * key/value pairs. As a shortcut, if the second argument
+         * is omitted and the key is a string, the setting is
+         * assumed to be the DSN string used by PDO to connect
+         * to the database (often, this will be the only configuration
+         * required to use Idiorm). If you have more than one setting
+         * you wish to configure, another shortcut is to pass an array
+         * of settings (and omit the second argument).
+         * @param string|array $key
+         * @param mixed $value
+         * @param string $connection_name Which connection to use
+         */
+        public static function configure($key, $value = null, $connection_name = self::DEFAULT_CONNECTION) {
+            self::_setup_db_config($connection_name); //ensures at least default config is set
+
+            if (is_array($key)) {
+                // Shortcut: If only one array argument is passed,
+                // assume it's an array of configuration settings
+                foreach ($key as $conf_key => $conf_value) {
+                    self::configure($conf_key, $conf_value, $connection_name);
+                }
             } else {
-                $query = str_replace("?", "%s", $query);
+                if (is_null($value)) {
+                    // Shortcut: If only one string argument is passed,
+                    // assume it's a connection string
+                    $value = $key;
+                    $key = 'connection_string';
+                }
+                self::$_config[$connection_name][$key] = $value;
+            }
+        }
+
+        /**
+         * Retrieve configuration options by key, or as whole array.
+         * @param string $key
+         * @param string $connection_name Which connection to use
+         */
+        public static function get_config($key = null, $connection_name = self::DEFAULT_CONNECTION) {
+            if ($key) {
+                return self::$_config[$connection_name][$key];
+            } else {
+                return self::$_config[$connection_name];
+            }
+        }
+
+        /**
+         * Delete all configs in _config array.
+         */
+        public static function reset_config() {
+            self::$_config = array();
+        }
+
+        /**
+         * Despite its slightly odd name, this is actually the factory
+         * method used to acquire instances of the class. It is named
+         * this way for the sake of a readable interface, ie
+         * ORM::for_table('table_name')->find_one()-> etc. As such,
+         * this will normally be the first method called in a chain.
+         * @param string $table_name
+         * @param string $connection_name Which connection to use
+         * @return ORM
+         */
+        public static function for_table($table_name, $connection_name = self::DEFAULT_CONNECTION) {
+            self::_setup_db($connection_name);
+            return new self($table_name, array(), $connection_name);
+        }
+
+        /**
+         * Set up the database connection used by the class
+         * @param string $connection_name Which connection to use
+         */
+        protected static function _setup_db($connection_name = self::DEFAULT_CONNECTION) {
+            if (!array_key_exists($connection_name, self::$_db) ||
+                !is_object(self::$_db[$connection_name])) {
+                self::_setup_db_config($connection_name);
+
+                $db = new PDO(
+                    self::$_config[$connection_name]['connection_string'],
+                    self::$_config[$connection_name]['username'],
+                    self::$_config[$connection_name]['password'],
+                    self::$_config[$connection_name]['driver_options']
+                );
+
+                $db->setAttribute(PDO::ATTR_ERRMODE, self::$_config[$connection_name]['error_mode']);
+                self::set_db($db, $connection_name);
+            }
+        }
+
+       /**
+        * Ensures configuration (multiple connections) is at least set to default.
+        * @param string $connection_name Which connection to use
+        */
+        protected static function _setup_db_config($connection_name) {
+            if (!array_key_exists($connection_name, self::$_config)) {
+                self::$_config[$connection_name] = self::$_default_config;
+            }
+        }
+
+        /**
+         * Set the PDO object used by Idiorm to communicate with the database.
+         * This is public in case the ORM should use a ready-instantiated
+         * PDO object as its database connection. Accepts an optional string key
+         * to identify the connection if multiple connections are used.
+         * @param PDO $db
+         * @param string $connection_name Which connection to use
+         */
+        public static function set_db($db, $connection_name = self::DEFAULT_CONNECTION) {
+            self::_setup_db_config($connection_name);
+            self::$_db[$connection_name] = $db;
+            if(!is_null(self::$_db[$connection_name])) {
+                self::_setup_identifier_quote_character($connection_name);
+                self::_setup_limit_clause_style($connection_name);
+            }
+        }
+
+        /**
+         * Close and delete all registered PDO objects in _db array.
+         */
+        public static function reset_db() {
+            self::$_db = null;
+
+            self::$_db = array();
+        }
+
+        /**
+         * Detect and initialise the character used to quote identifiers
+         * (table names, column names etc). If this has been specified
+         * manually using ORM::configure('identifier_quote_character', 'some-char'),
+         * this will do nothing.
+         * @param string $connection_name Which connection to use
+         */
+        protected static function _setup_identifier_quote_character($connection_name) {
+            if (is_null(self::$_config[$connection_name]['identifier_quote_character'])) {
+                self::$_config[$connection_name]['identifier_quote_character'] =
+                    self::_detect_identifier_quote_character($connection_name);
+            }
+        }
+
+        /**
+         * Detect and initialise the limit clause style ("SELECT TOP 5" /
+         * "... LIMIT 5"). If this has been specified manually using
+         * ORM::configure('limit_clause_style', 'top'), this will do nothing.
+         * @param string $connection_name Which connection to use
+         */
+        public static function _setup_limit_clause_style($connection_name) {
+            if (is_null(self::$_config[$connection_name]['limit_clause_style'])) {
+                self::$_config[$connection_name]['limit_clause_style'] =
+                    self::_detect_limit_clause_style($connection_name);
+            }
+        }
+
+        /**
+         * Return the correct character used to quote identifiers (table
+         * names, column names etc) by looking at the driver being used by PDO.
+         * @param string $connection_name Which connection to use
+         * @return string
+         */
+        protected static function _detect_identifier_quote_character($connection_name) {
+            switch(self::get_db($connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME)) {
+                case 'pgsql':
+                case 'sqlsrv':
+                case 'dblib':
+                case 'mssql':
+                case 'sybase':
+                case 'firebird':
+                    return '"';
+                case 'mysql':
+                case 'sqlite':
+                case 'sqlite2':
+                default:
+                    return '`';
+            }
+        }
+
+        /**
+         * Returns a constant after determining the appropriate limit clause
+         * style
+         * @param string $connection_name Which connection to use
+         * @return string Limit clause style keyword/constant
+         */
+        protected static function _detect_limit_clause_style($connection_name) {
+            switch(self::get_db($connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME)) {
+                case 'sqlsrv':
+                case 'dblib':
+                case 'mssql':
+                    return ORM::LIMIT_STYLE_TOP_N;
+                default:
+                    return ORM::LIMIT_STYLE_LIMIT;
+            }
+        }
+
+        /**
+         * Returns the PDO instance used by the the ORM to communicate with
+         * the database. This can be called if any low-level DB access is
+         * required outside the class. If multiple connections are used,
+         * accepts an optional key name for the connection.
+         * @param string $connection_name Which connection to use
+         * @return PDO
+         */
+        public static function get_db($connection_name = self::DEFAULT_CONNECTION) {
+            self::_setup_db($connection_name); // required in case this is called before Idiorm is instantiated
+            return self::$_db[$connection_name];
+        }
+
+        /**
+         * Executes a raw query as a wrapper for PDOStatement::execute.
+         * Useful for queries that can't be accomplished through Idiorm,
+         * particularly those using engine-specific features.
+         * @example raw_execute('SELECT `name`, AVG(`order`) FROM `customer` GROUP BY `name` HAVING AVG(`order`) > 10')
+         * @example raw_execute('INSERT OR REPLACE INTO `widget` (`id`, `name`) SELECT `id`, `name` FROM `other_table`')
+         * @param string $query The raw SQL query
+         * @param array  $parameters Optional bound parameters
+         * @param string $connection_name Which connection to use
+         * @return bool Success
+         */
+        public static function raw_execute($query, $parameters = array(), $connection_name = self::DEFAULT_CONNECTION) {
+            self::_setup_db($connection_name);
+            return self::_execute($query, $parameters, $connection_name);
+        }
+
+        /**
+         * Returns the PDOStatement instance last used by any connection wrapped by the ORM.
+         * Useful for access to PDOStatement::rowCount() or error information
+         * @return PDOStatement
+         */
+        public static function get_last_statement() {
+            return self::$_last_statement;
+        }
+
+       /**
+        * Internal helper method for executing statments. Logs queries, and
+        * stores statement object in ::_last_statment, accessible publicly
+        * through ::get_last_statement()
+        * @param string $query
+        * @param array $parameters An array of parameters to be bound in to the query
+        * @param string $connection_name Which connection to use
+        * @return bool Response of PDOStatement::execute()
+        */
+        protected static function _execute($query, $parameters = array(), $connection_name = self::DEFAULT_CONNECTION) {
+            $statement = self::get_db($connection_name)->prepare($query);
+            self::$_last_statement = $statement;
+            $time = microtime(true);
+
+            foreach ($parameters as $key => &$param) {
+                if (is_null($param)) {
+                    $type = PDO::PARAM_NULL;
+                } else if (is_bool($param)) {
+                    $type = PDO::PARAM_BOOL;
+                } else if (is_int($param)) {
+                    $type = PDO::PARAM_INT;
+                } else {
+                    $type = PDO::PARAM_STR;
+                }
+
+                $statement->bindParam(is_int($key) ? ++$key : $key, $param, $type);
             }
 
-            // Replace the question marks in the query with the parameters
-            $bound_query = vsprintf($query, $parameters);
-        } else {
-            $bound_query = $query;
+            $q = $statement->execute();
+            self::_log_query($query, $parameters, $connection_name, (microtime(true)-$time));
+
+            return $q;
         }
 
-        self::$_last_query = $bound_query;
-        self::$_query_log[$connection_name][] = $bound_query;
+        /**
+         * Add a query to the internal query log. Only works if the
+         * 'logging' config option is set to true.
+         *
+         * This works by manually binding the parameters to the query - the
+         * query isn't executed like this (PDO normally passes the query and
+         * parameters to the database which takes care of the binding) but
+         * doing it this way makes the logged queries more readable.
+         * @param string $query
+         * @param array $parameters An array of parameters to be bound in to the query
+         * @param string $connection_name Which connection to use
+		 * @param float $query_time Query time
+         * @return bool
+         */
+        protected static function _log_query($query, $parameters, $connection_name, $query_time) {
+            // If logging is not enabled, do nothing
+            if (!self::$_config[$connection_name]['logging']) {
+                return false;
+            }
+
+            if (!isset(self::$_query_log[$connection_name])) {
+                self::$_query_log[$connection_name] = array();
+            }
+
+            if (empty($parameters)) {
+                $bound_query = $query;
+            } else {
+                // Escape the parameters
+                $parameters = array_map(array(self::get_db($connection_name), 'quote'), $parameters);
+
+                if (array_values($parameters) === $parameters) {
+                    // ? placeholders
+                    // Avoid %format collision for vsprintf
+                    $query = str_replace("%", "%%", $query);
+
+                    // Replace placeholders in the query for vsprintf
+                    if(false !== strpos($query, "'") || false !== strpos($query, '"')) {
+                        $query = IdiormString::str_replace_outside_quotes("?", "%s", $query);
+                    } else {
+                        $query = str_replace("?", "%s", $query);
+                    }
+
+                    // Replace the question marks in the query with the parameters
+                    $bound_query = vsprintf($query, $parameters);
+                } else {
+                    // named placeholders
+                    foreach ($parameters as $key => $val) {
+                        $query = str_replace($key, $val, $query);
+                    }
+                    $bound_query = $query;
+                }
+            }
+
+            self::$_last_query = $bound_query;
+            self::$_query_log[$connection_name][] = $bound_query;
 
 
-        if(is_callable(self::$_config[$connection_name]['logger'])){
-            $logger = self::$_config[$connection_name]['logger'];
-            $logger($bound_query, $query_time);
+            if(is_callable(self::$_config[$connection_name]['logger'])){
+                $logger = self::$_config[$connection_name]['logger'];
+                $logger($bound_query, $query_time);
+            }
+
+            return true;
         }
 
-        return true;
-    }
+        /**
+         * Get the last query executed. Only works if the
+         * 'logging' config option is set to true. Otherwise
+         * this will return null. Returns last query from all connections if
+         * no connection_name is specified
+         * @param null|string $connection_name Which connection to use
+         * @return string
+         */
+        public static function get_last_query($connection_name = null) {
+            if ($connection_name === null) {
+                return self::$_last_query;
+            }
+            if (!isset(self::$_query_log[$connection_name])) {
+                return '';
+            }
 
-    /**
-     * Get the last query executed. Only works if the
-     * 'logging' config option is set to true. Otherwise
-     * this will return null. Returns last query from all connections if
-     * no connection_name is specified
-     * @param null|string $connection_name Which connection to use
-     * @return string
-     */
-    public static function get_last_query($connection_name = null) {
-        if ($connection_name === null) {
-            return self::$_last_query;
+            return end(self::$_query_log[$connection_name]);
         }
-        if (!isset(self::$_query_log[$connection_name])) {
+
+        /**
+         * Get an array containing all the queries run on a
+         * specified connection up to now.
+         * Only works if the 'logging' config option is
+         * set to true. Otherwise, returned array will be empty.
+         * @param string $connection_name Which connection to use
+         */
+        public static function get_query_log($connection_name = self::DEFAULT_CONNECTION) {
+            if (isset(self::$_query_log[$connection_name])) {
+                return self::$_query_log[$connection_name];
+            }
+            return array();
+        }
+
+        /**
+         * Get a list of the available connection names
+         * @return array
+         */
+        public static function get_connection_names() {
+            return array_keys(self::$_db);
+        }
+
+        // ------------------------ //
+        // --- INSTANCE METHODS --- //
+        // ------------------------ //
+
+        /**
+         * "Private" constructor; shouldn't be called directly.
+         * Use the ORM::for_table factory method instead.
+         */
+        protected function __construct($table_name, $data = array(), $connection_name = self::DEFAULT_CONNECTION) {
+            $this->_table_name = $table_name;
+            $this->_data = $data;
+
+            $this->_connection_name = $connection_name;
+            self::_setup_db_config($connection_name);
+        }
+
+        /**
+         * Create a new, empty instance of the class. Used
+         * to add a new row to your database. May optionally
+         * be passed an associative array of data to populate
+         * the instance. If so, all fields will be flagged as
+         * dirty so all will be saved to the database when
+         * save() is called.
+         */
+        public function create($data=null) {
+            $this->_is_new = true;
+            if (!is_null($data)) {
+                return $this->hydrate($data)->force_all_dirty();
+            }
+            return $this;
+        }
+
+        /**
+         * Specify the ID column to use for this instance or array of instances only.
+         * This overrides the id_column and id_column_overrides settings.
+         *
+         * This is mostly useful for libraries built on top of Idiorm, and will
+         * not normally be used in manually built queries. If you don't know why
+         * you would want to use this, you should probably just ignore it.
+         */
+        public function use_id_column($id_column) {
+            $this->_instance_id_column = $id_column;
+            return $this;
+        }
+
+        /**
+         * Create an ORM instance from the given row (an associative
+         * array of data fetched from the database)
+         */
+        protected function _create_instance_from_row($row) {
+            $instance = self::for_table($this->_table_name, $this->_connection_name);
+            $instance->use_id_column($this->_instance_id_column);
+            $instance->hydrate($row);
+            return $instance;
+        }
+
+        /**
+         * Tell the ORM that you are expecting a single result
+         * back from your query, and execute it. Will return
+         * a single instance of the ORM class, or false if no
+         * rows were returned.
+         * As a shortcut, you may supply an ID as a parameter
+         * to this method. This will perform a primary key
+         * lookup on the table.
+         */
+        public function find_one($id=null) {
+            if (!is_null($id)) {
+                $this->where_id_is($id);
+            }
+            $this->limit(1);
+            $rows = $this->_run();
+
+            if (empty($rows)) {
+                return false;
+            }
+
+            return $this->_create_instance_from_row($rows[0]);
+        }
+
+        /**
+         * Tell the ORM that you are expecting multiple results
+         * from your query, and execute it. Will return an array
+         * of instances of the ORM class, or an empty array if
+         * no rows were returned.
+         * @return array|\IdiormResultSet
+         */
+        public function find_many() {
+            if(self::$_config[$this->_connection_name]['return_result_sets']) {
+                return $this->find_result_set();
+            }
+            return $this->_find_many();
+        }
+
+        /**
+         * Tell the ORM that you are expecting multiple results
+         * from your query, and execute it. Will return an array
+         * of instances of the ORM class, or an empty array if
+         * no rows were returned.
+         * @return array
+         */
+        protected function _find_many() {
+            $rows = $this->_run();
+            return array_map(array($this, '_create_instance_from_row'), $rows);
+        }
+
+        /**
+         * Tell the ORM that you are expecting multiple results
+         * from your query, and execute it. Will return a result set object
+         * containing instances of the ORM class.
+         * @return \IdiormResultSet
+         */
+        public function find_result_set() {
+            return new IdiormResultSet($this->_find_many());
+        }
+
+        /**
+         * Tell the ORM that you are expecting multiple results
+         * from your query, and execute it. Will return an array,
+         * or an empty array if no rows were returned.
+         * @return array
+         */
+        public function find_array() {
+            return $this->_run();
+        }
+
+        /**
+         * Tell the ORM that you wish to execute a COUNT query.
+         * Will return an integer representing the number of
+         * rows returned.
+         */
+        public function count($column = '*') {
+            return $this->_call_aggregate_db_function(__FUNCTION__, $column);
+        }
+
+        /**
+         * Tell the ORM that you wish to execute a MAX query.
+         * Will return the max value of the choosen column.
+         */
+        public function max($column)  {
+            return $this->_call_aggregate_db_function(__FUNCTION__, $column);
+        }
+
+        /**
+         * Tell the ORM that you wish to execute a MIN query.
+         * Will return the min value of the choosen column.
+         */
+        public function min($column)  {
+            return $this->_call_aggregate_db_function(__FUNCTION__, $column);
+        }
+
+        /**
+         * Tell the ORM that you wish to execute a AVG query.
+         * Will return the average value of the choosen column.
+         */
+        public function avg($column)  {
+            return $this->_call_aggregate_db_function(__FUNCTION__, $column);
+        }
+
+        /**
+         * Tell the ORM that you wish to execute a SUM query.
+         * Will return the sum of the choosen column.
+         */
+        public function sum($column)  {
+            return $this->_call_aggregate_db_function(__FUNCTION__, $column);
+        }
+
+        /**
+         * Execute an aggregate query on the current connection.
+         * @param string $sql_function The aggregate function to call eg. MIN, COUNT, etc
+         * @param string $column The column to execute the aggregate query against
+         * @return int
+         */
+        protected function _call_aggregate_db_function($sql_function, $column) {
+            $alias = strtolower($sql_function);
+            $sql_function = strtoupper($sql_function);
+            if('*' != $column) {
+                $column = $this->_quote_identifier($column);
+            }
+            $result_columns = $this->_result_columns;
+            $this->_result_columns = array();
+            $this->select_expr("$sql_function($column)", $alias);
+            $result = $this->find_one();
+            $this->_result_columns = $result_columns;
+
+            $return_value = 0;
+            if($result !== false && isset($result->$alias)) {
+                if (!is_numeric($result->$alias)) {
+                    $return_value = $result->$alias;
+                }
+                elseif((int) $result->$alias == (float) $result->$alias) {
+                    $return_value = (int) $result->$alias;
+                } else {
+                    $return_value = (float) $result->$alias;
+                }
+            }
+            return $return_value;
+        }
+
+         /**
+         * This method can be called to hydrate (populate) this
+         * instance of the class from an associative array of data.
+         * This will usually be called only from inside the class,
+         * but it's public in case you need to call it directly.
+         */
+        public function hydrate($data=array()) {
+            $this->_data = $data;
+            return $this;
+        }
+
+        /**
+         * Force the ORM to flag all the fields in the $data array
+         * as "dirty" and therefore update them when save() is called.
+         */
+        public function force_all_dirty() {
+            $this->_dirty_fields = $this->_data;
+            return $this;
+        }
+
+        /**
+         * Perform a raw query. The query can contain placeholders in
+         * either named or question mark style. If placeholders are
+         * used, the parameters should be an array of values which will
+         * be bound to the placeholders in the query. If this method
+         * is called, all other query building methods will be ignored.
+         */
+        public function raw_query($query, $parameters = array()) {
+            $this->_is_raw_query = true;
+            $this->_raw_query = $query;
+            $this->_raw_parameters = $parameters;
+            return $this;
+        }
+
+        /**
+         * Add an alias for the main table to be used in SELECT queries
+         */
+        public function table_alias($alias) {
+            $this->_table_alias = $alias;
+            return $this;
+        }
+
+        /**
+         * Internal method to add an unquoted expression to the set
+         * of columns returned by the SELECT query. The second optional
+         * argument is the alias to return the expression as.
+         */
+        protected function _add_result_column($expr, $alias=null) {
+            if (!is_null($alias)) {
+                $expr .= " AS " . $this->_quote_identifier($alias);
+            }
+
+            if ($this->_using_default_result_columns) {
+                $this->_result_columns = array($expr);
+                $this->_using_default_result_columns = false;
+            } else {
+                $this->_result_columns[] = $expr;
+            }
+            return $this;
+        }
+
+        /**
+         * Counts the number of columns that belong to the primary
+         * key and their value is null.
+         */
+        public function count_null_id_columns() {
+            if (is_array($this->_get_id_column_name())) {
+                return count(array_filter($this->id(), 'is_null'));
+            } else {
+                return is_null($this->id()) ? 1 : 0;
+            }
+        }
+
+        /**
+         * Add a column to the list of columns returned by the SELECT
+         * query. This defaults to '*'. The second optional argument is
+         * the alias to return the column as.
+         */
+        public function select($column, $alias=null) {
+            $column = $this->_quote_identifier($column);
+            return $this->_add_result_column($column, $alias);
+        }
+
+        /**
+         * Add an unquoted expression to the list of columns returned
+         * by the SELECT query. The second optional argument is
+         * the alias to return the column as.
+         */
+        public function select_expr($expr, $alias=null) {
+            return $this->_add_result_column($expr, $alias);
+        }
+
+        /**
+         * Add columns to the list of columns returned by the SELECT
+         * query. This defaults to '*'. Many columns can be supplied
+         * as either an array or as a list of parameters to the method.
+         *
+         * Note that the alias must not be numeric - if you want a
+         * numeric alias then prepend it with some alpha chars. eg. a1
+         *
+         * @example select_many(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5');
+         * @example select_many('column', 'column2', 'column3');
+         * @example select_many(array('column', 'column2', 'column3'), 'column4', 'column5');
+         *
+         * @return \ORM
+         */
+        public function select_many() {
+            $columns = func_get_args();
+            if(!empty($columns)) {
+                $columns = $this->_normalise_select_many_columns($columns);
+                foreach($columns as $alias => $column) {
+                    if(is_numeric($alias)) {
+                        $alias = null;
+                    }
+                    $this->select($column, $alias);
+                }
+            }
+            return $this;
+        }
+
+        /**
+         * Add an unquoted expression to the list of columns returned
+         * by the SELECT query. Many columns can be supplied as either
+         * an array or as a list of parameters to the method.
+         *
+         * Note that the alias must not be numeric - if you want a
+         * numeric alias then prepend it with some alpha chars. eg. a1
+         *
+         * @example select_many_expr(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5')
+         * @example select_many_expr('column', 'column2', 'column3')
+         * @example select_many_expr(array('column', 'column2', 'column3'), 'column4', 'column5')
+         *
+         * @return \ORM
+         */
+        public function select_many_expr() {
+            $columns = func_get_args();
+            if(!empty($columns)) {
+                $columns = $this->_normalise_select_many_columns($columns);
+                foreach($columns as $alias => $column) {
+                    if(is_numeric($alias)) {
+                        $alias = null;
+                    }
+                    $this->select_expr($column, $alias);
+                }
+            }
+            return $this;
+        }
+
+        /**
+         * Take a column specification for the select many methods and convert it
+         * into a normalised array of columns and aliases.
+         *
+         * It is designed to turn the following styles into a normalised array:
+         *
+         * array(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5'))
+         *
+         * @param array $columns
+         * @return array
+         */
+        protected function _normalise_select_many_columns($columns) {
+            $return = array();
+            foreach($columns as $column) {
+                if(is_array($column)) {
+                    foreach($column as $key => $value) {
+                        if(!is_numeric($key)) {
+                            $return[$key] = $value;
+                        } else {
+                            $return[] = $value;
+                        }
+                    }
+                } else {
+                    $return[] = $column;
+                }
+            }
+            return $return;
+        }
+
+        /**
+         * Add a DISTINCT keyword before the list of columns in the SELECT query
+         */
+        public function distinct() {
+            $this->_distinct = true;
+            return $this;
+        }
+
+        /**
+         * Internal method to add a JOIN source to the query.
+         *
+         * The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this
+         * will be prepended to JOIN.
+         *
+         * The table should be the name of the table to join to.
+         *
+         * The constraint may be either a string or an array with three elements. If it
+         * is a string, it will be compiled into the query as-is, with no escaping. The
+         * recommended way to supply the constraint is as an array with three elements:
+         *
+         * first_column, operator, second_column
+         *
+         * Example: array('user.id', '=', 'profile.user_id')
+         *
+         * will compile to
+         *
+         * ON `user`.`id` = `profile`.`user_id`
+         *
+         * The final (optional) argument specifies an alias for the joined table.
+         */
+        protected function _add_join_source($join_operator, $table, $constraint, $table_alias=null) {
+
+            $join_operator = trim("{$join_operator} JOIN");
+
+            $table = $this->_quote_identifier($table);
+
+            // Add table alias if present
+            if (!is_null($table_alias)) {
+                $table_alias = $this->_quote_identifier($table_alias);
+                $table .= " {$table_alias}";
+            }
+
+            // Build the constraint
+            if (is_array($constraint)) {
+                list($first_column, $operator, $second_column) = $constraint;
+                $first_column = $this->_quote_identifier($first_column);
+                $second_column = $this->_quote_identifier($second_column);
+                $constraint = "{$first_column} {$operator} {$second_column}";
+            }
+
+            $this->_join_sources[] = "{$join_operator} {$table} ON {$constraint}";
+            return $this;
+        }
+
+        /**
+         * Add a RAW JOIN source to the query
+         */
+        public function raw_join($table, $constraint, $table_alias, $parameters = array()) {
+            // Add table alias if present
+            if (!is_null($table_alias)) {
+                $table_alias = $this->_quote_identifier($table_alias);
+                $table .= " {$table_alias}";
+            }
+
+            $this->_values = array_merge($this->_values, $parameters);
+
+            // Build the constraint
+            if (is_array($constraint)) {
+                list($first_column, $operator, $second_column) = $constraint;
+                $first_column = $this->_quote_identifier($first_column);
+                $second_column = $this->_quote_identifier($second_column);
+                $constraint = "{$first_column} {$operator} {$second_column}";
+            }
+
+            $this->_join_sources[] = "{$table} ON {$constraint}";
+            return $this;
+        }
+
+        /**
+         * Add a simple JOIN source to the query
+         */
+        public function join($table, $constraint, $table_alias=null) {
+            return $this->_add_join_source("", $table, $constraint, $table_alias);
+        }
+
+        /**
+         * Add an INNER JOIN souce to the query
+         */
+        public function inner_join($table, $constraint, $table_alias=null) {
+            return $this->_add_join_source("INNER", $table, $constraint, $table_alias);
+        }
+
+        /**
+         * Add a LEFT OUTER JOIN souce to the query
+         */
+        public function left_outer_join($table, $constraint, $table_alias=null) {
+            return $this->_add_join_source("LEFT OUTER", $table, $constraint, $table_alias);
+        }
+
+        /**
+         * Add an RIGHT OUTER JOIN souce to the query
+         */
+        public function right_outer_join($table, $constraint, $table_alias=null) {
+            return $this->_add_join_source("RIGHT OUTER", $table, $constraint, $table_alias);
+        }
+
+        /**
+         * Add an FULL OUTER JOIN souce to the query
+         */
+        public function full_outer_join($table, $constraint, $table_alias=null) {
+            return $this->_add_join_source("FULL OUTER", $table, $constraint, $table_alias);
+        }
+
+        /**
+         * Internal method to add a HAVING condition to the query
+         */
+        protected function _add_having($fragment, $values=array()) {
+            return $this->_add_condition('having', $fragment, $values);
+        }
+
+        /**
+         * Internal method to add a HAVING condition to the query
+         */
+        protected function _add_simple_having($column_name, $separator, $value) {
+            return $this->_add_simple_condition('having', $column_name, $separator, $value);
+        }
+
+        /**
+         * Internal method to add a HAVING clause with multiple values (like IN and NOT IN)
+         */
+        public function _add_having_placeholder($column_name, $separator, $values) {
+            if (!is_array($column_name)) {
+                $data = array($column_name => $values);
+            } else {
+                $data = $column_name;
+            }
+            $result = $this;
+            foreach ($data as $key => $val) {
+                $column = $result->_quote_identifier($key);
+                $placeholders = $result->_create_placeholders($val);
+                $result = $result->_add_having("{$column} {$separator} ({$placeholders})", $val);
+            }
+            return $result;
+        }
+
+        /**
+         * Internal method to add a HAVING clause with no parameters(like IS NULL and IS NOT NULL)
+         */
+        public function _add_having_no_value($column_name, $operator) {
+            $conditions = (is_array($column_name)) ? $column_name : array($column_name);
+            $result = $this;
+            foreach($conditions as $column) {
+                $column = $this->_quote_identifier($column);
+                $result = $result->_add_having("{$column} {$operator}");
+            }
+            return $result;
+        }
+
+        /**
+         * Internal method to add a WHERE condition to the query
+         */
+        protected function _add_where($fragment, $values=array()) {
+            return $this->_add_condition('where', $fragment, $values);
+        }
+
+        /**
+         * Internal method to add a WHERE condition to the query
+         */
+        protected function _add_simple_where($column_name, $separator, $value) {
+            return $this->_add_simple_condition('where', $column_name, $separator, $value);
+        }
+
+        /**
+         * Add a WHERE clause with multiple values (like IN and NOT IN)
+         */
+        public function _add_where_placeholder($column_name, $separator, $values) {
+            if (!is_array($column_name)) {
+                $data = array($column_name => $values);
+            } else {
+                $data = $column_name;
+            }
+            $result = $this;
+            foreach ($data as $key => $val) {
+                $column = $result->_quote_identifier($key);
+                $placeholders = $result->_create_placeholders($val);
+                $result = $result->_add_where("{$column} {$separator} ({$placeholders})", $val);
+            }
+            return $result;
+        }
+
+        /**
+         * Add a WHERE clause with no parameters(like IS NULL and IS NOT NULL)
+         */
+        public function _add_where_no_value($column_name, $operator) {
+            $conditions = (is_array($column_name)) ? $column_name : array($column_name);
+            $result = $this;
+            foreach($conditions as $column) {
+                $column = $this->_quote_identifier($column);
+                $result = $result->_add_where("{$column} {$operator}");
+            }
+            return $result;
+        }
+
+        /**
+         * Internal method to add a HAVING or WHERE condition to the query
+         */
+        protected function _add_condition($type, $fragment, $values=array()) {
+            $conditions_class_property_name = "_{$type}_conditions";
+            if (!is_array($values)) {
+                $values = array($values);
+            }
+            array_push($this->$conditions_class_property_name, array(
+                self::CONDITION_FRAGMENT => $fragment,
+                self::CONDITION_VALUES => $values,
+            ));
+            return $this;
+        }
+
+       /**
+         * Helper method to compile a simple COLUMN SEPARATOR VALUE
+         * style HAVING or WHERE condition into a string and value ready to
+         * be passed to the _add_condition method. Avoids duplication
+         * of the call to _quote_identifier
+         *
+         * If column_name is an associative array, it will add a condition for each column
+         */
+        protected function _add_simple_condition($type, $column_name, $separator, $value) {
+            $multiple = is_array($column_name) ? $column_name : array($column_name => $value);
+            $result = $this;
+
+            foreach($multiple as $key => $val) {
+                // Add the table name in case of ambiguous columns
+                if (count($result->_join_sources) > 0 && strpos($key, '.') === false) {
+                    $table = $result->_table_name;
+                    if (!is_null($result->_table_alias)) {
+                        $table = $result->_table_alias;
+                    }
+
+                    $key = "{$table}.{$key}";
+                }
+                $key = $result->_quote_identifier($key);
+                $result = $result->_add_condition($type, "{$key} {$separator} ?", $val);
+            }
+            return $result;
+        }
+
+        /**
+         * Return a string containing the given number of question marks,
+         * separated by commas. Eg "?, ?, ?"
+         */
+        protected function _create_placeholders($fields) {
+            if(!empty($fields)) {
+                $db_fields = array();
+                foreach($fields as $key => $value) {
+                    // Process expression fields directly into the query
+                    if(array_key_exists($key, $this->_expr_fields)) {
+                        $db_fields[] = $value;
+                    } else {
+                        $db_fields[] = '?';
+                    }
+                }
+                return implode(', ', $db_fields);
+            }
+        }
+
+        /**
+         * Helper method that filters a column/value array returning only those
+         * columns that belong to a compound primary key.
+         *
+         * If the key contains a column that does not exist in the given array,
+         * a null value will be returned for it.
+         */
+        protected function _get_compound_id_column_values($value) {
+            $filtered = array();
+            foreach($this->_get_id_column_name() as $key) {
+                $filtered[$key] = isset($value[$key]) ? $value[$key] : null;
+            }
+            return $filtered;
+        }
+
+       /**
+         * Helper method that filters an array containing compound column/value
+         * arrays.
+         */
+        protected function _get_compound_id_column_values_array($values) {
+            $filtered = array();
+            foreach($values as $value) {
+                $filtered[] = $this->_get_compound_id_column_values($value);
+            }
+            return $filtered;
+        }
+
+        /**
+         * Add a WHERE column = value clause to your query. Each time
+         * this is called in the chain, an additional WHERE will be
+         * added, and these will be ANDed together when the final query
+         * is built.
+         *
+         * If you use an array in $column_name, a new clause will be
+         * added for each element. In this case, $value is ignored.
+         */
+        public function where($column_name, $value=null) {
+            return $this->where_equal($column_name, $value);
+        }
+
+        /**
+         * More explicitly named version of for the where() method.
+         * Can be used if preferred.
+         */
+        public function where_equal($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '=', $value);
+        }
+
+        /**
+         * Add a WHERE column != value clause to your query.
+         */
+        public function where_not_equal($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '!=', $value);
+        }
+
+        /**
+         * Special method to query the table by its primary key
+         *
+         * If primary key is compound, only the columns that
+         * belong to they key will be used for the query
+         */
+        public function where_id_is($id) {
+            return (is_array($this->_get_id_column_name())) ?
+                $this->where($this->_get_compound_id_column_values($id), null) :
+                $this->where($this->_get_id_column_name(), $id);
+        }
+
+        /**
+         * Allows adding a WHERE clause that matches any of the conditions
+         * specified in the array. Each element in the associative array will
+         * be a different condition, where the key will be the column name.
+         *
+         * By default, an equal operator will be used against all columns, but
+         * it can be overriden for any or every column using the second parameter.
+         *
+         * Each condition will be ORed together when added to the final query.
+         */
+        public function where_any_is($values, $operator='=') {
+            $data = array();
+            $query = array("((");
+            $first = true;
+            foreach ($values as $value) {
+                if ($first) {
+                    $first = false;
+                } else {
+                    $query[] = ") OR (";
+                }
+                $firstsub = true;
+                foreach($value as $key => $item) {
+                    $op = is_string($operator) ? $operator : (isset($operator[$key]) ? $operator[$key] : '=');
+                    if ($firstsub) {
+                        $firstsub = false;
+                    } else {
+                        $query[] = "AND";
+                    }
+                    $query[] = $this->_quote_identifier($key);
+                    $data[] = $item;
+                    $query[] = $op . " ?";
+                }
+            }
+            $query[] = "))";
+            return $this->where_raw(join(' ', $query), $data);
+        }
+
+        /**
+         * Similar to where_id_is() but allowing multiple primary keys.
+         *
+         * If primary key is compound, only the columns that
+         * belong to they key will be used for the query
+         */
+        public function where_id_in($ids) {
+            return (is_array($this->_get_id_column_name())) ?
+                $this->where_any_is($this->_get_compound_id_column_values_array($ids)) :
+                $this->where_in($this->_get_id_column_name(), $ids);
+        }
+
+        /**
+         * Add a WHERE ... LIKE clause to your query.
+         */
+        public function where_like($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, 'LIKE', $value);
+        }
+
+        /**
+         * Add where WHERE ... NOT LIKE clause to your query.
+         */
+        public function where_not_like($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, 'NOT LIKE', $value);
+        }
+
+        /**
+         * Add a WHERE ... > clause to your query
+         */
+        public function where_gt($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '>', $value);
+        }
+
+        /**
+         * Add a WHERE ... < clause to your query
+         */
+        public function where_lt($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '<', $value);
+        }
+
+        /**
+         * Add a WHERE ... >= clause to your query
+         */
+        public function where_gte($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '>=', $value);
+        }
+
+        /**
+         * Add a WHERE ... <= clause to your query
+         */
+        public function where_lte($column_name, $value=null) {
+            return $this->_add_simple_where($column_name, '<=', $value);
+        }
+
+        /**
+         * Add a WHERE ... IN clause to your query
+         */
+        public function where_in($column_name, $values) {
+            return $this->_add_where_placeholder($column_name, 'IN', $values);
+        }
+
+        /**
+         * Add a WHERE ... NOT IN clause to your query
+         */
+        public function where_not_in($column_name, $values) {
+            return $this->_add_where_placeholder($column_name, 'NOT IN', $values);
+        }
+
+        /**
+         * Add a WHERE column IS NULL clause to your query
+         */
+        public function where_null($column_name) {
+            return $this->_add_where_no_value($column_name, "IS NULL");
+        }
+
+        /**
+         * Add a WHERE column IS NOT NULL clause to your query
+         */
+        public function where_not_null($column_name) {
+            return $this->_add_where_no_value($column_name, "IS NOT NULL");
+        }
+
+        /**
+         * Add a raw WHERE clause to the query. The clause should
+         * contain question mark placeholders, which will be bound
+         * to the parameters supplied in the second argument.
+         */
+        public function where_raw($clause, $parameters=array()) {
+            return $this->_add_where($clause, $parameters);
+        }
+
+        /**
+         * Add a LIMIT to the query
+         */
+        public function limit($limit) {
+            $this->_limit = $limit;
+            return $this;
+        }
+
+        /**
+         * Add an OFFSET to the query
+         */
+        public function offset($offset) {
+            $this->_offset = $offset;
+            return $this;
+        }
+
+        /**
+         * Add an ORDER BY clause to the query
+         */
+        protected function _add_order_by($column_name, $ordering) {
+            $column_name = $this->_quote_identifier($column_name);
+            $this->_order_by[] = "{$column_name} {$ordering}";
+            return $this;
+        }
+
+        /**
+         * Add an ORDER BY column DESC clause
+         */
+        public function order_by_desc($column_name) {
+            return $this->_add_order_by($column_name, 'DESC');
+        }
+
+        /**
+         * Add an ORDER BY column ASC clause
+         */
+        public function order_by_asc($column_name) {
+            return $this->_add_order_by($column_name, 'ASC');
+        }
+
+        /**
+         * Add an unquoted expression as an ORDER BY clause
+         */
+        public function order_by_expr($clause) {
+            $this->_order_by[] = $clause;
+            return $this;
+        }
+
+        /**
+         * Add a column to the list of columns to GROUP BY
+         */
+        public function group_by($column_name) {
+            $column_name = $this->_quote_identifier($column_name);
+            $this->_group_by[] = $column_name;
+            return $this;
+        }
+
+        /**
+         * Add an unquoted expression to the list of columns to GROUP BY
+         */
+        public function group_by_expr($expr) {
+            $this->_group_by[] = $expr;
+            return $this;
+        }
+
+        /**
+         * Add a HAVING column = value clause to your query. Each time
+         * this is called in the chain, an additional HAVING will be
+         * added, and these will be ANDed together when the final query
+         * is built.
+         *
+         * If you use an array in $column_name, a new clause will be
+         * added for each element. In this case, $value is ignored.
+         */
+        public function having($column_name, $value=null) {
+            return $this->having_equal($column_name, $value);
+        }
+
+        /**
+         * More explicitly named version of for the having() method.
+         * Can be used if preferred.
+         */
+        public function having_equal($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '=', $value);
+        }
+
+        /**
+         * Add a HAVING column != value clause to your query.
+         */
+        public function having_not_equal($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '!=', $value);
+        }
+
+        /**
+         * Special method to query the table by its primary key.
+         *
+         * If primary key is compound, only the columns that
+         * belong to they key will be used for the query
+         */
+        public function having_id_is($id) {
+            return (is_array($this->_get_id_column_name())) ?
+                $this->having($this->_get_compound_id_column_values($id), null) :
+                $this->having($this->_get_id_column_name(), $id);
+        }
+
+        /**
+         * Add a HAVING ... LIKE clause to your query.
+         */
+        public function having_like($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, 'LIKE', $value);
+        }
+
+        /**
+         * Add where HAVING ... NOT LIKE clause to your query.
+         */
+        public function having_not_like($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, 'NOT LIKE', $value);
+        }
+
+        /**
+         * Add a HAVING ... > clause to your query
+         */
+        public function having_gt($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '>', $value);
+        }
+
+        /**
+         * Add a HAVING ... < clause to your query
+         */
+        public function having_lt($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '<', $value);
+        }
+
+        /**
+         * Add a HAVING ... >= clause to your query
+         */
+        public function having_gte($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '>=', $value);
+        }
+
+        /**
+         * Add a HAVING ... <= clause to your query
+         */
+        public function having_lte($column_name, $value=null) {
+            return $this->_add_simple_having($column_name, '<=', $value);
+        }
+
+        /**
+         * Add a HAVING ... IN clause to your query
+         */
+        public function having_in($column_name, $values=null) {
+            return $this->_add_having_placeholder($column_name, 'IN', $values);
+        }
+
+        /**
+         * Add a HAVING ... NOT IN clause to your query
+         */
+        public function having_not_in($column_name, $values=null) {
+            return $this->_add_having_placeholder($column_name, 'NOT IN', $values);
+        }
+
+        /**
+         * Add a HAVING column IS NULL clause to your query
+         */
+        public function having_null($column_name) {
+            return $this->_add_having_no_value($column_name, 'IS NULL');
+        }
+
+        /**
+         * Add a HAVING column IS NOT NULL clause to your query
+         */
+        public function having_not_null($column_name) {
+            return $this->_add_having_no_value($column_name, 'IS NOT NULL');
+        }
+
+        /**
+         * Add a raw HAVING clause to the query. The clause should
+         * contain question mark placeholders, which will be bound
+         * to the parameters supplied in the second argument.
+         */
+        public function having_raw($clause, $parameters=array()) {
+            return $this->_add_having($clause, $parameters);
+        }
+
+        /**
+         * Build a SELECT statement based on the clauses that have
+         * been passed to this instance by chaining method calls.
+         */
+        protected function _build_select() {
+            // If the query is raw, just set the $this->_values to be
+            // the raw query parameters and return the raw query
+            if ($this->_is_raw_query) {
+                $this->_values = $this->_raw_parameters;
+                return $this->_raw_query;
+            }
+
+            // Build and return the full SELECT statement by concatenating
+            // the results of calling each separate builder method.
+            return $this->_join_if_not_empty(" ", array(
+                $this->_build_select_start(),
+                $this->_build_join(),
+                $this->_build_where(),
+                $this->_build_group_by(),
+                $this->_build_having(),
+                $this->_build_order_by(),
+                $this->_build_limit(),
+                $this->_build_offset(),
+            ));
+        }
+
+        /**
+         * Build the start of the SELECT statement
+         */
+        protected function _build_select_start() {
+            $fragment = 'SELECT ';
+            $result_columns = join(', ', $this->_result_columns);
+
+            if (!is_null($this->_limit) &&
+                self::$_config[$this->_connection_name]['limit_clause_style'] === ORM::LIMIT_STYLE_TOP_N) {
+                $fragment .= "TOP {$this->_limit} ";
+            }
+
+            if ($this->_distinct) {
+                $result_columns = 'DISTINCT ' . $result_columns;
+            }
+
+            $fragment .= "{$result_columns} FROM " . $this->_quote_identifier($this->_table_name);
+
+            if (!is_null($this->_table_alias)) {
+                $fragment .= " " . $this->_quote_identifier($this->_table_alias);
+            }
+            return $fragment;
+        }
+
+        /**
+         * Build the JOIN sources
+         */
+        protected function _build_join() {
+            if (count($this->_join_sources) === 0) {
+                return '';
+            }
+
+            return join(" ", $this->_join_sources);
+        }
+
+        /**
+         * Build the WHERE clause(s)
+         */
+        protected function _build_where() {
+            return $this->_build_conditions('where');
+        }
+
+        /**
+         * Build the HAVING clause(s)
+         */
+        protected function _build_having() {
+            return $this->_build_conditions('having');
+        }
+
+        /**
+         * Build GROUP BY
+         */
+        protected function _build_group_by() {
+            if (count($this->_group_by) === 0) {
+                return '';
+            }
+            return "GROUP BY " . join(", ", $this->_group_by);
+        }
+
+        /**
+         * Build a WHERE or HAVING clause
+         * @param string $type
+         * @return string
+         */
+        protected function _build_conditions($type) {
+            $conditions_class_property_name = "_{$type}_conditions";
+            // If there are no clauses, return empty string
+            if (count($this->$conditions_class_property_name) === 0) {
+                return '';
+            }
+
+            $conditions = array();
+            foreach ($this->$conditions_class_property_name as $condition) {
+                $conditions[] = $condition[self::CONDITION_FRAGMENT];
+                $this->_values = array_merge($this->_values, $condition[self::CONDITION_VALUES]);
+            }
+
+            return strtoupper($type) . " " . join(" AND ", $conditions);
+        }
+
+        /**
+         * Build ORDER BY
+         */
+        protected function _build_order_by() {
+            if (count($this->_order_by) === 0) {
+                return '';
+            }
+            return "ORDER BY " . join(", ", $this->_order_by);
+        }
+
+        /**
+         * Build LIMIT
+         */
+        protected function _build_limit() {
+            $fragment = '';
+            if (!is_null($this->_limit) &&
+                self::$_config[$this->_connection_name]['limit_clause_style'] == ORM::LIMIT_STYLE_LIMIT) {
+                if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'firebird') {
+                    $fragment = 'ROWS';
+                } else {
+                    $fragment = 'LIMIT';
+                }
+                $fragment .= " {$this->_limit}";
+            }
+            return $fragment;
+        }
+
+        /**
+         * Build OFFSET
+         */
+        protected function _build_offset() {
+            if (!is_null($this->_offset)) {
+                $clause = 'OFFSET';
+                if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'firebird') {
+                    $clause = 'TO';
+                }
+                return "$clause " . $this->_offset;
+            }
             return '';
         }
 
-        return end(self::$_query_log[$connection_name]);
-    }
-
-    /**
-     * Get an array containing all the queries run on a
-     * specified connection up to now.
-     * Only works if the 'logging' config option is
-     * set to true. Otherwise, returned array will be empty.
-     * @param string $connection_name Which connection to use
-     */
-    public static function get_query_log($connection_name = self::DEFAULT_CONNECTION) {
-        if (isset(self::$_query_log[$connection_name])) {
-            return self::$_query_log[$connection_name];
+        /**
+         * Wrapper around PHP's join function which
+         * only adds the pieces if they are not empty.
+         */
+        protected function _join_if_not_empty($glue, $pieces) {
+            $filtered_pieces = array();
+            foreach ($pieces as $piece) {
+                if (is_string($piece)) {
+                    $piece = trim($piece);
+                }
+                if (!empty($piece)) {
+                    $filtered_pieces[] = $piece;
+                }
+            }
+            return join($glue, $filtered_pieces);
         }
-        return array();
-    }
 
-    /**
-     * Get a list of the available connection names
-     * @return array
-     */
-    public static function get_connection_names() {
-        return array_keys(self::$_db);
-    }
-
-    // ------------------------ //
-    // --- INSTANCE METHODS --- //
-    // ------------------------ //
-
-    /**
-     * "Private" constructor; shouldn't be called directly.
-     * Use the ORM::for_table factory method instead.
-     */
-    protected function __construct($table_name, $data = array(), $connection_name = self::DEFAULT_CONNECTION) {
-        $this->_table_name = $table_name;
-        $this->_data = $data;
-
-        $this->_connection_name = $connection_name;
-        self::_setup_db_config($connection_name);
-    }
-
-    /**
-     * Create a new, empty instance of the class. Used
-     * to add a new row to your database. May optionally
-     * be passed an associative array of data to populate
-     * the instance. If so, all fields will be flagged as
-     * dirty so all will be saved to the database when
-     * save() is called.
-     */
-    public function create($data=null) {
-        $this->_is_new = true;
-        if (!is_null($data)) {
-            return $this->hydrate($data)->force_all_dirty();
+        /**
+         * Quote a string that is used as an identifier
+         * (table names, column names etc). This method can
+         * also deal with dot-separated identifiers eg table.column
+         */
+        protected function _quote_one_identifier($identifier) {
+            $parts = explode('.', $identifier);
+            $parts = array_map(array($this, '_quote_identifier_part'), $parts);
+            return join('.', $parts);
         }
-        return $this;
-    }
 
-    /**
-     * Specify the ID column to use for this instance or array of instances only.
-     * This overrides the id_column and id_column_overrides settings.
-     *
-     * This is mostly useful for libraries built on top of Idiorm, and will
-     * not normally be used in manually built queries. If you don't know why
-     * you would want to use this, you should probably just ignore it.
-     */
-    public function use_id_column($id_column) {
-        $this->_instance_id_column = $id_column;
-        return $this;
-    }
-
-    /**
-     * Create an ORM instance from the given row (an associative
-     * array of data fetched from the database)
-     */
-    protected function _create_instance_from_row($row) {
-        $instance = self::for_table($this->_table_name, $this->_connection_name);
-        $instance->use_id_column($this->_instance_id_column);
-        $instance->hydrate($row);
-        return $instance;
-    }
-
-    /**
-     * Tell the ORM that you are expecting a single result
-     * back from your query, and execute it. Will return
-     * a single instance of the ORM class, or false if no
-     * rows were returned.
-     * As a shortcut, you may supply an ID as a parameter
-     * to this method. This will perform a primary key
-     * lookup on the table.
-     */
-    public function find_one($id=null) {
-        if (!is_null($id)) {
-            $this->where_id_is($id);
+        /**
+         * Quote a string that is used as an identifier
+         * (table names, column names etc) or an array containing
+         * multiple identifiers. This method can also deal with
+         * dot-separated identifiers eg table.column
+         */
+        protected function _quote_identifier($identifier) {
+            if (is_array($identifier)) {
+                $result = array_map(array($this, '_quote_one_identifier'), $identifier);
+                return join(', ', $result);
+            } else {
+                return $this->_quote_one_identifier($identifier);
+            }
         }
-        $this->limit(1);
-        $rows = $this->_run();
 
-        if (empty($rows)) {
+        /**
+         * This method performs the actual quoting of a single
+         * part of an identifier, using the identifier quote
+         * character specified in the config (or autodetected).
+         */
+        protected function _quote_identifier_part($part) {
+            if ($part === '*') {
+                return $part;
+            }
+
+            $quote_character = self::$_config[$this->_connection_name]['identifier_quote_character'];
+            // double up any identifier quotes to escape them
+            return $quote_character .
+                   str_replace($quote_character,
+                               $quote_character . $quote_character,
+                               $part
+                   ) . $quote_character;
+        }
+
+        /**
+         * Create a cache key for the given query and parameters.
+         */
+        protected static function _create_cache_key($query, $parameters, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
+            if(isset(self::$_config[$connection_name]['create_cache_key']) and is_callable(self::$_config[$connection_name]['create_cache_key'])){
+                return call_user_func_array(self::$_config[$connection_name]['create_cache_key'], array($query, $parameters, $table_name, $connection_name));
+            }
+            $parameter_string = join(',', $parameters);
+            $key = $query . ':' . $parameter_string;
+            return sha1($key);
+        }
+
+        /**
+         * Check the query cache for the given cache key. If a value
+         * is cached for the key, return the value. Otherwise, return false.
+         */
+        protected static function _check_query_cache($cache_key, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
+            if(isset(self::$_config[$connection_name]['check_query_cache']) and is_callable(self::$_config[$connection_name]['check_query_cache'])){
+                return call_user_func_array(self::$_config[$connection_name]['check_query_cache'], array($cache_key, $table_name, $connection_name));
+            } elseif (isset(self::$_query_cache[$connection_name][$cache_key])) {
+                return self::$_query_cache[$connection_name][$cache_key];
+            }
             return false;
         }
 
-        return $this->_create_instance_from_row($rows[0]);
-    }
-
-    /**
-     * Tell the ORM that you are expecting multiple results
-     * from your query, and execute it. Will return an array
-     * of instances of the ORM class, or an empty array if
-     * no rows were returned.
-     * @return array|\IdiormResultSet
-     */
-    public function find_many() {
-        if(self::$_config[$this->_connection_name]['return_result_sets']) {
-            return $this->find_result_set();
-        }
-        return $this->_find_many();
-    }
-
-    /**
-     * Tell the ORM that you are expecting multiple results
-     * from your query, and execute it. Will return an array
-     * of instances of the ORM class, or an empty array if
-     * no rows were returned.
-     * @return array
-     */
-    protected function _find_many() {
-        $rows = $this->_run();
-        return array_map(array($this, '_create_instance_from_row'), $rows);
-    }
-
-    /**
-     * Tell the ORM that you are expecting multiple results
-     * from your query, and execute it. Will return a result set object
-     * containing instances of the ORM class.
-     * @return \IdiormResultSet
-     */
-    public function find_result_set() {
-        return new IdiormResultSet($this->_find_many());
-    }
-
-    /**
-     * Tell the ORM that you are expecting multiple results
-     * from your query, and execute it. Will return an array,
-     * or an empty array if no rows were returned.
-     * @return array
-     */
-    public function find_array() {
-        return $this->_run();
-    }
-
-    /**
-     * Tell the ORM that you wish to execute a COUNT query.
-     * Will return an integer representing the number of
-     * rows returned.
-     */
-    public function count($column = '*') {
-        return $this->_call_aggregate_db_function(__FUNCTION__, $column);
-    }
-
-    /**
-     * Tell the ORM that you wish to execute a MAX query.
-     * Will return the max value of the choosen column.
-     */
-    public function max($column)  {
-        return $this->_call_aggregate_db_function(__FUNCTION__, $column);
-    }
-
-    /**
-     * Tell the ORM that you wish to execute a MIN query.
-     * Will return the min value of the choosen column.
-     */
-    public function min($column)  {
-        return $this->_call_aggregate_db_function(__FUNCTION__, $column);
-    }
-
-    /**
-     * Tell the ORM that you wish to execute a AVG query.
-     * Will return the average value of the choosen column.
-     */
-    public function avg($column)  {
-        return $this->_call_aggregate_db_function(__FUNCTION__, $column);
-    }
-
-    /**
-     * Tell the ORM that you wish to execute a SUM query.
-     * Will return the sum of the choosen column.
-     */
-    public function sum($column)  {
-        return $this->_call_aggregate_db_function(__FUNCTION__, $column);
-    }
-
-    /**
-     * Execute an aggregate query on the current connection.
-     * @param string $sql_function The aggregate function to call eg. MIN, COUNT, etc
-     * @param string $column The column to execute the aggregate query against
-     * @return int
-     */
-    protected function _call_aggregate_db_function($sql_function, $column) {
-        $alias = strtolower($sql_function);
-        $sql_function = strtoupper($sql_function);
-        if('*' != $column) {
-            $column = $this->_quote_identifier($column);
-        }
-        $result_columns = $this->_result_columns;
-        $this->_result_columns = array();
-        $this->select_expr("$sql_function($column)", $alias);
-        $result = $this->find_one();
-        $this->_result_columns = $result_columns;
-
-        $return_value = 0;
-        if($result !== false && isset($result->$alias)) {
-            if (!is_numeric($result->$alias)) {
-                $return_value = $result->$alias;
+        /**
+         * Clear the query cache
+         */
+        public static function clear_cache($table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
+            self::$_query_cache = array();
+            if(isset(self::$_config[$connection_name]['clear_cache']) and is_callable(self::$_config[$connection_name]['clear_cache'])){
+                return call_user_func_array(self::$_config[$connection_name]['clear_cache'], array($table_name, $connection_name));
             }
-            elseif((int) $result->$alias == (float) $result->$alias) {
-                $return_value = (int) $result->$alias;
+        }
+
+        /**
+         * Add the given value to the query cache.
+         */
+        protected static function _cache_query_result($cache_key, $value, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
+            if(isset(self::$_config[$connection_name]['cache_query_result']) and is_callable(self::$_config[$connection_name]['cache_query_result'])){
+                return call_user_func_array(self::$_config[$connection_name]['cache_query_result'], array($cache_key, $value, $table_name, $connection_name));
+            } elseif (!isset(self::$_query_cache[$connection_name])) {
+                self::$_query_cache[$connection_name] = array();
+            }
+            self::$_query_cache[$connection_name][$cache_key] = $value;
+        }
+
+        /**
+         * Execute the SELECT query that has been built up by chaining methods
+         * on this class. Return an array of rows as associative arrays.
+         */
+        protected function _run() {
+            $query = $this->_build_select();
+            $caching_enabled = self::$_config[$this->_connection_name]['caching'];
+
+            if ($caching_enabled) {
+                $cache_key = self::_create_cache_key($query, $this->_values, $this->_table_name, $this->_connection_name);
+                $cached_result = self::_check_query_cache($cache_key, $this->_table_name, $this->_connection_name);
+
+                if ($cached_result !== false) {
+                    $this->_reset_idiorm_state();
+                    return $cached_result;
+                }
+            }
+
+            self::_execute($query, $this->_values, $this->_connection_name);
+            $statement = self::get_last_statement();
+
+            $rows = array();
+            while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
+                $rows[] = $row;
+            }
+
+            if ($caching_enabled) {
+                self::_cache_query_result($cache_key, $rows, $this->_table_name, $this->_connection_name);
+            }
+
+            $this->_reset_idiorm_state();
+            return $rows;
+        }
+
+        /**
+         * Reset the Idiorm instance state
+         */
+        private function _reset_idiorm_state() {
+            $this->_values = array();
+            $this->_result_columns = array('*');
+            $this->_using_default_result_columns = true;
+        }
+
+        /**
+         * Return the raw data wrapped by this ORM
+         * instance as an associative array. Column
+         * names may optionally be supplied as arguments,
+         * if so, only those keys will be returned.
+         */
+        public function as_array() {
+            if (func_num_args() === 0) {
+                return $this->_data;
+            }
+            $args = func_get_args();
+            return array_intersect_key($this->_data, array_flip($args));
+        }
+
+        /**
+         * Return the value of a property of this object (database row)
+         * or null if not present.
+         *
+         * If a column-names array is passed, it will return a associative array
+         * with the value of each column or null if it is not present.
+         */
+        public function get($key) {
+            if (is_array($key)) {
+                $result = array();
+                foreach($key as $column) {
+                    $result[$column] = isset($this->_data[$column]) ? $this->_data[$column] : null;
+                }
+                return $result;
             } else {
-                $return_value = (float) $result->$alias;
+                return isset($this->_data[$key]) ? $this->_data[$key] : null;
             }
         }
-        return $return_value;
-    }
 
-    /**
-     * This method can be called to hydrate (populate) this
-     * instance of the class from an associative array of data.
-     * This will usually be called only from inside the class,
-     * but it's public in case you need to call it directly.
-     */
-    public function hydrate($data=array()) {
-        $this->_data = $data;
-        return $this;
-    }
-
-    /**
-     * Force the ORM to flag all the fields in the $data array
-     * as "dirty" and therefore update them when save() is called.
-     */
-    public function force_all_dirty() {
-        $this->_dirty_fields = $this->_data;
-        return $this;
-    }
-
-    /**
-     * Perform a raw query. The query can contain placeholders in
-     * either named or question mark style. If placeholders are
-     * used, the parameters should be an array of values which will
-     * be bound to the placeholders in the query. If this method
-     * is called, all other query building methods will be ignored.
-     */
-    public function raw_query($query, $parameters = array()) {
-        $this->_is_raw_query = true;
-        $this->_raw_query = $query;
-        $this->_raw_parameters = $parameters;
-        return $this;
-    }
-
-    /**
-     * Add an alias for the main table to be used in SELECT queries
-     */
-    public function table_alias($alias) {
-        $this->_table_alias = $alias;
-        return $this;
-    }
-
-    /**
-     * Internal method to add an unquoted expression to the set
-     * of columns returned by the SELECT query. The second optional
-     * argument is the alias to return the expression as.
-     */
-    protected function _add_result_column($expr, $alias=null) {
-        if (!is_null($alias)) {
-            $expr .= " AS " . $this->_quote_identifier($alias);
+        /**
+         * Return the name of the column in the database table which contains
+         * the primary key ID of the row.
+         */
+        protected function _get_id_column_name() {
+            if (!is_null($this->_instance_id_column)) {
+                return $this->_instance_id_column;
+            }
+            if (isset(self::$_config[$this->_connection_name]['id_column_overrides'][$this->_table_name])) {
+                return self::$_config[$this->_connection_name]['id_column_overrides'][$this->_table_name];
+            }
+            return self::$_config[$this->_connection_name]['id_column'];
         }
 
-        if ($this->_using_default_result_columns) {
-            $this->_result_columns = array($expr);
-            $this->_using_default_result_columns = false;
-        } else {
-            $this->_result_columns[] = $expr;
-        }
-        return $this;
-    }
+        /**
+         * Get the primary key ID of this object.
+         */
+        public function id($disallow_null = false) {
+            $id = $this->get($this->_get_id_column_name());
 
-    /**
-     * Counts the number of columns that belong to the primary
-     * key and their value is null.
-     */
-    public function count_null_id_columns() {
-        if (is_array($this->_get_id_column_name())) {
-            return count(array_filter($this->id(), 'is_null'));
-        } else {
-            return is_null($this->id()) ? 1 : 0;
-        }
-    }
-
-    /**
-     * Add a column to the list of columns returned by the SELECT
-     * query. This defaults to '*'. The second optional argument is
-     * the alias to return the column as.
-     */
-    public function select($column, $alias=null) {
-        $column = $this->_quote_identifier($column);
-        return $this->_add_result_column($column, $alias);
-    }
-
-    /**
-     * Add an unquoted expression to the list of columns returned
-     * by the SELECT query. The second optional argument is
-     * the alias to return the column as.
-     */
-    public function select_expr($expr, $alias=null) {
-        return $this->_add_result_column($expr, $alias);
-    }
-
-    /**
-     * Add columns to the list of columns returned by the SELECT
-     * query. This defaults to '*'. Many columns can be supplied
-     * as either an array or as a list of parameters to the method.
-     *
-     * Note that the alias must not be numeric - if you want a
-     * numeric alias then prepend it with some alpha chars. eg. a1
-     *
-     * @example select_many(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5');
-     * @example select_many('column', 'column2', 'column3');
-     * @example select_many(array('column', 'column2', 'column3'), 'column4', 'column5');
-     *
-     * @return \ORM
-     */
-    public function select_many() {
-        $columns = func_get_args();
-        if(!empty($columns)) {
-            $columns = $this->_normalise_select_many_columns($columns);
-            foreach($columns as $alias => $column) {
-                if(is_numeric($alias)) {
-                    $alias = null;
+            if ($disallow_null) {
+                if (is_array($id)) {
+                    foreach ($id as $id_part) {
+                        if ($id_part === null) {
+                            throw new Exception('Primary key ID contains null value(s)');
+                        }
+                    }
+                } else if ($id === null) {
+                    throw new Exception('Primary key ID missing from row or is null');
                 }
-                $this->select($column, $alias);
             }
-        }
-        return $this;
-    }
 
-    /**
-     * Add an unquoted expression to the list of columns returned
-     * by the SELECT query. Many columns can be supplied as either
-     * an array or as a list of parameters to the method.
-     *
-     * Note that the alias must not be numeric - if you want a
-     * numeric alias then prepend it with some alpha chars. eg. a1
-     *
-     * @example select_many_expr(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5')
-     * @example select_many_expr('column', 'column2', 'column3')
-     * @example select_many_expr(array('column', 'column2', 'column3'), 'column4', 'column5')
-     *
-     * @return \ORM
-     */
-    public function select_many_expr() {
-        $columns = func_get_args();
-        if(!empty($columns)) {
-            $columns = $this->_normalise_select_many_columns($columns);
-            foreach($columns as $alias => $column) {
-                if(is_numeric($alias)) {
-                    $alias = null;
+            return $id;
+        }
+
+        /**
+         * Set a property to a particular value on this object.
+         * To set multiple properties at once, pass an associative array
+         * as the first parameter and leave out the second parameter.
+         * Flags the properties as 'dirty' so they will be saved to the
+         * database when save() is called.
+         */
+        public function set($key, $value = null) {
+            return $this->_set_orm_property($key, $value);
+        }
+
+        /**
+         * Set a property to a particular value on this object.
+         * To set multiple properties at once, pass an associative array
+         * as the first parameter and leave out the second parameter.
+         * Flags the properties as 'dirty' so they will be saved to the
+         * database when save() is called.
+         * @param string|array $key
+         * @param string|null $value
+         */
+        public function set_expr($key, $value = null) {
+            return $this->_set_orm_property($key, $value, true);
+        }
+
+        /**
+         * Set a property on the ORM object.
+         * @param string|array $key
+         * @param string|null $value
+         * @param bool $raw Whether this value should be treated as raw or not
+         */
+        protected function _set_orm_property($key, $value = null, $expr = false) {
+            if (!is_array($key)) {
+                $key = array($key => $value);
+            }
+            foreach ($key as $field => $value) {
+                $this->_data[$field] = $value;
+                $this->_dirty_fields[$field] = $value;
+                if (false === $expr and isset($this->_expr_fields[$field])) {
+                    unset($this->_expr_fields[$field]);
+                } else if (true === $expr) {
+                    $this->_expr_fields[$field] = true;
                 }
-                $this->select_expr($column, $alias);
             }
+            return $this;
         }
-        return $this;
-    }
 
-    /**
-     * Take a column specification for the select many methods and convert it
-     * into a normalised array of columns and aliases.
-     *
-     * It is designed to turn the following styles into a normalised array:
-     *
-     * array(array('alias' => 'column', 'column2', 'alias2' => 'column3'), 'column4', 'column5'))
-     *
-     * @param array $columns
-     * @return array
-     */
-    protected function _normalise_select_many_columns($columns) {
-        $return = array();
-        foreach($columns as $column) {
-            if(is_array($column)) {
-                foreach($column as $key => $value) {
-                    if(!is_numeric($key)) {
-                        $return[$key] = $value;
+        /**
+         * Check whether the given field has been changed since this
+         * object was saved.
+         */
+        public function is_dirty($key) {
+            return array_key_exists($key, $this->_dirty_fields);
+        }
+
+        /**
+         * Check whether the model was the result of a call to create() or not
+         * @return bool
+         */
+        public function is_new() {
+            return $this->_is_new;
+        }
+
+        /**
+         * Save any fields which have been modified on this object
+         * to the database.
+         */
+        public function save() {
+            $query = array();
+
+            // remove any expression fields as they are already baked into the query
+            $values = array_values(array_diff_key($this->_dirty_fields, $this->_expr_fields));
+
+            if (!$this->_is_new) { // UPDATE
+                // If there are no dirty values, do nothing
+                if (empty($values) && empty($this->_expr_fields)) {
+                    return true;
+                }
+                $query = $this->_build_update();
+                $id = $this->id(true);
+                if (is_array($id)) {
+                    $values = array_merge($values, array_values($id));
+                } else {
+                    $values[] = $id;
+                }
+            } else { // INSERT
+                $query = $this->_build_insert();
+            }
+
+            $success = self::_execute($query, $values, $this->_connection_name);
+            $caching_auto_clear_enabled = self::$_config[$this->_connection_name]['caching_auto_clear'];
+            if($caching_auto_clear_enabled){
+                self::clear_cache($this->_table_name, $this->_connection_name);
+            }
+            // If we've just inserted a new record, set the ID of this object
+            if ($this->_is_new) {
+                $this->_is_new = false;
+                if ($this->count_null_id_columns() != 0) {
+                    $db = self::get_db($this->_connection_name);
+                    if($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'pgsql') {
+                        // it may return several columns if a compound primary
+                        // key is used
+                        $row = self::get_last_statement()->fetch(PDO::FETCH_ASSOC);
+                        foreach($row as $key => $value) {
+                            $this->_data[$key] = $value;
+                        }
                     } else {
-                        $return[] = $value;
+                        $column = $this->_get_id_column_name();
+                        // if the primary key is compound, assign the last inserted id
+                        // to the first column
+                        if (is_array($column)) {
+                            $column = reset($column);
+                        }
+                        $this->_data[$column] = $db->lastInsertId();
                     }
                 }
-            } else {
-                $return[] = $column;
             }
-        }
-        return $return;
-    }
 
-    /**
-     * Add a DISTINCT keyword before the list of columns in the SELECT query
-     */
-    public function distinct() {
-        $this->_distinct = true;
-        return $this;
-    }
-
-    /**
-     * Internal method to add a JOIN source to the query.
-     *
-     * The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this
-     * will be prepended to JOIN.
-     *
-     * The table should be the name of the table to join to.
-     *
-     * The constraint may be either a string or an array with three elements. If it
-     * is a string, it will be compiled into the query as-is, with no escaping. The
-     * recommended way to supply the constraint is as an array with three elements:
-     *
-     * first_column, operator, second_column
-     *
-     * Example: array('user.id', '=', 'profile.user_id')
-     *
-     * will compile to
-     *
-     * ON `user`.`id` = `profile`.`user_id`
-     *
-     * The final (optional) argument specifies an alias for the joined table.
-     */
-    protected function _add_join_source($join_operator, $table, $constraint, $table_alias=null) {
-
-        $join_operator = trim("{$join_operator} JOIN");
-
-        $table = $this->_quote_identifier($table);
-
-        // Add table alias if present
-        if (!is_null($table_alias)) {
-            $table_alias = $this->_quote_identifier($table_alias);
-            $table .= " {$table_alias}";
+            $this->_dirty_fields = $this->_expr_fields = array();
+            return $success;
         }
 
-        // Build the constraint
-        if (is_array($constraint)) {
-            list($first_column, $operator, $second_column) = $constraint;
-            $first_column = $this->_quote_identifier($first_column);
-            $second_column = $this->_quote_identifier($second_column);
-            $constraint = "{$first_column} {$operator} {$second_column}";
-        }
-
-        $this->_join_sources[] = "{$join_operator} {$table} ON {$constraint}";
-        return $this;
-    }
-
-    /**
-     * Add a RAW JOIN source to the query
-     */
-    public function raw_join($table, $constraint, $table_alias, $parameters = array()) {
-        // Add table alias if present
-        if (!is_null($table_alias)) {
-            $table_alias = $this->_quote_identifier($table_alias);
-            $table .= " {$table_alias}";
-        }
-
-        $this->_values = array_merge($this->_values, $parameters);
-
-        // Build the constraint
-        if (is_array($constraint)) {
-            list($first_column, $operator, $second_column) = $constraint;
-            $first_column = $this->_quote_identifier($first_column);
-            $second_column = $this->_quote_identifier($second_column);
-            $constraint = "{$first_column} {$operator} {$second_column}";
-        }
-
-        $this->_join_sources[] = "{$table} ON {$constraint}";
-        return $this;
-    }
-
-    /**
-     * Add a simple JOIN source to the query
-     */
-    public function join($table, $constraint, $table_alias=null) {
-        return $this->_add_join_source("", $table, $constraint, $table_alias);
-    }
-
-    /**
-     * Add an INNER JOIN souce to the query
-     */
-    public function inner_join($table, $constraint, $table_alias=null) {
-        return $this->_add_join_source("INNER", $table, $constraint, $table_alias);
-    }
-
-    /**
-     * Add a LEFT OUTER JOIN souce to the query
-     */
-    public function left_outer_join($table, $constraint, $table_alias=null) {
-        return $this->_add_join_source("LEFT OUTER", $table, $constraint, $table_alias);
-    }
-
-    /**
-     * Add an RIGHT OUTER JOIN souce to the query
-     */
-    public function right_outer_join($table, $constraint, $table_alias=null) {
-        return $this->_add_join_source("RIGHT OUTER", $table, $constraint, $table_alias);
-    }
-
-    /**
-     * Add an FULL OUTER JOIN souce to the query
-     */
-    public function full_outer_join($table, $constraint, $table_alias=null) {
-        return $this->_add_join_source("FULL OUTER", $table, $constraint, $table_alias);
-    }
-
-    /**
-     * Internal method to add a HAVING condition to the query
-     */
-    protected function _add_having($fragment, $values=array()) {
-        return $this->_add_condition('having', $fragment, $values);
-    }
-
-    /**
-     * Internal method to add a HAVING condition to the query
-     */
-    protected function _add_simple_having($column_name, $separator, $value) {
-        return $this->_add_simple_condition('having', $column_name, $separator, $value);
-    }
-
-    /**
-     * Internal method to add a HAVING clause with multiple values (like IN and NOT IN)
-     */
-    public function _add_having_placeholder($column_name, $separator, $values) {
-        if (!is_array($column_name)) {
-            $data = array($column_name => $values);
-        } else {
-            $data = $column_name;
-        }
-        $result = $this;
-        foreach ($data as $key => $val) {
-            $column = $result->_quote_identifier($key);
-            $placeholders = $result->_create_placeholders($val);
-            $result = $result->_add_having("{$column} {$separator} ({$placeholders})", $val);
-        }
-        return $result;
-    }
-
-    /**
-     * Internal method to add a HAVING clause with no parameters(like IS NULL and IS NOT NULL)
-     */
-    public function _add_having_no_value($column_name, $operator) {
-        $conditions = (is_array($column_name)) ? $column_name : array($column_name);
-        $result = $this;
-        foreach($conditions as $column) {
-            $column = $this->_quote_identifier($column);
-            $result = $result->_add_having("{$column} {$operator}");
-        }
-        return $result;
-    }
-
-    /**
-     * Internal method to add a WHERE condition to the query
-     */
-    protected function _add_where($fragment, $values=array()) {
-        return $this->_add_condition('where', $fragment, $values);
-    }
-
-    /**
-     * Internal method to add a WHERE condition to the query
-     */
-    protected function _add_simple_where($column_name, $separator, $value) {
-        return $this->_add_simple_condition('where', $column_name, $separator, $value);
-    }
-
-    /**
-     * Add a WHERE clause with multiple values (like IN and NOT IN)
-     */
-    public function _add_where_placeholder($column_name, $separator, $values) {
-        if (!is_array($column_name)) {
-            $data = array($column_name => $values);
-        } else {
-            $data = $column_name;
-        }
-        $result = $this;
-        foreach ($data as $key => $val) {
-            $column = $result->_quote_identifier($key);
-            $placeholders = $result->_create_placeholders($val);
-            $result = $result->_add_where("{$column} {$separator} ({$placeholders})", $val);
-        }
-        return $result;
-    }
-
-    /**
-     * Add a WHERE clause with no parameters(like IS NULL and IS NOT NULL)
-     */
-    public function _add_where_no_value($column_name, $operator) {
-        $conditions = (is_array($column_name)) ? $column_name : array($column_name);
-        $result = $this;
-        foreach($conditions as $column) {
-            $column = $this->_quote_identifier($column);
-            $result = $result->_add_where("{$column} {$operator}");
-        }
-        return $result;
-    }
-
-    /**
-     * Internal method to add a HAVING or WHERE condition to the query
-     */
-    protected function _add_condition($type, $fragment, $values=array()) {
-        $conditions_class_property_name = "_{$type}_conditions";
-        if (!is_array($values)) {
-            $values = array($values);
-        }
-        array_push($this->$conditions_class_property_name, array(
-            self::CONDITION_FRAGMENT => $fragment,
-            self::CONDITION_VALUES => $values,
-        ));
-        return $this;
-    }
-
-    /**
-     * Helper method to compile a simple COLUMN SEPARATOR VALUE
-     * style HAVING or WHERE condition into a string and value ready to
-     * be passed to the _add_condition method. Avoids duplication
-     * of the call to _quote_identifier
-     *
-     * If column_name is an associative array, it will add a condition for each column
-     */
-    protected function _add_simple_condition($type, $column_name, $separator, $value) {
-        $multiple = is_array($column_name) ? $column_name : array($column_name => $value);
-        $result = $this;
-
-        foreach($multiple as $key => $val) {
-            // Add the table name in case of ambiguous columns
-            if (count($result->_join_sources) > 0 && strpos($key, '.') === false) {
-                $table = $result->_table_name;
-                if (!is_null($result->_table_alias)) {
-                    $table = $result->_table_alias;
+        /**
+         * Add a WHERE clause for every column that belongs to the primary key
+         */
+        public function _add_id_column_conditions(&$query) {
+            $query[] = "WHERE";
+            $keys = is_array($this->_get_id_column_name()) ? $this->_get_id_column_name() : array( $this->_get_id_column_name() );
+            $first = true;
+            foreach($keys as $key) {
+                if ($first) {
+                    $first = false;
                 }
-
-                $key = "{$table}.{$key}";
-            }
-            $key = $result->_quote_identifier($key);
-            $result = $result->_add_condition($type, "{$key} {$separator} ?", $val);
-        }
-        return $result;
-    }
-
-    /**
-     * Return a string containing the given number of question marks,
-     * separated by commas. Eg "?, ?, ?"
-     */
-    protected function _create_placeholders($fields) {
-        if(!empty($fields)) {
-            $db_fields = array();
-            foreach($fields as $key => $value) {
-                // Process expression fields directly into the query
-                if(array_key_exists($key, $this->_expr_fields)) {
-                    $db_fields[] = $value;
-                } else {
-                    $db_fields[] = '?';
-                }
-            }
-            return implode(', ', $db_fields);
-        }
-    }
-
-    /**
-     * Helper method that filters a column/value array returning only those
-     * columns that belong to a compound primary key.
-     *
-     * If the key contains a column that does not exist in the given array,
-     * a null value will be returned for it.
-     */
-    protected function _get_compound_id_column_values($value) {
-        $filtered = array();
-        foreach($this->_get_id_column_name() as $key) {
-            $filtered[$key] = isset($value[$key]) ? $value[$key] : null;
-        }
-        return $filtered;
-    }
-
-    /**
-     * Helper method that filters an array containing compound column/value
-     * arrays.
-     */
-    protected function _get_compound_id_column_values_array($values) {
-        $filtered = array();
-        foreach($values as $value) {
-            $filtered[] = $this->_get_compound_id_column_values($value);
-        }
-        return $filtered;
-    }
-
-    /**
-     * Add a WHERE column = value clause to your query. Each time
-     * this is called in the chain, an additional WHERE will be
-     * added, and these will be ANDed together when the final query
-     * is built.
-     *
-     * If you use an array in $column_name, a new clause will be
-     * added for each element. In this case, $value is ignored.
-     */
-    public function where($column_name, $value=null) {
-        return $this->where_equal($column_name, $value);
-    }
-
-    /**
-     * More explicitly named version of for the where() method.
-     * Can be used if preferred.
-     */
-    public function where_equal($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '=', $value);
-    }
-
-    /**
-     * Add a WHERE column != value clause to your query.
-     */
-    public function where_not_equal($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '!=', $value);
-    }
-
-    /**
-     * Special method to query the table by its primary key
-     *
-     * If primary key is compound, only the columns that
-     * belong to they key will be used for the query
-     */
-    public function where_id_is($id) {
-        return (is_array($this->_get_id_column_name())) ?
-            $this->where($this->_get_compound_id_column_values($id), null) :
-            $this->where($this->_get_id_column_name(), $id);
-    }
-
-    /**
-     * Allows adding a WHERE clause that matches any of the conditions
-     * specified in the array. Each element in the associative array will
-     * be a different condition, where the key will be the column name.
-     *
-     * By default, an equal operator will be used against all columns, but
-     * it can be overriden for any or every column using the second parameter.
-     *
-     * Each condition will be ORed together when added to the final query.
-     */
-    public function where_any_is($values, $operator='=') {
-        $data = array();
-        $query = array("((");
-        $first = true;
-        foreach ($values as $item) {
-            if ($first) {
-                $first = false;
-            } else {
-                $query[] = ") OR (";
-            }
-            $firstsub = true;
-            foreach($item as $key => $item) {
-                $op = is_string($operator) ? $operator : (isset($operator[$key]) ? $operator[$key] : '=');
-                if ($firstsub) {
-                    $firstsub = false;
-                } else {
+                else {
                     $query[] = "AND";
                 }
                 $query[] = $this->_quote_identifier($key);
-                $data[] = $item;
-                $query[] = $op . " ?";
-            }
-        }
-        $query[] = "))";
-        return $this->where_raw(join($query, ' '), $data);
-    }
-
-    /**
-     * Similar to where_id_is() but allowing multiple primary keys.
-     *
-     * If primary key is compound, only the columns that
-     * belong to they key will be used for the query
-     */
-    public function where_id_in($ids) {
-        return (is_array($this->_get_id_column_name())) ?
-            $this->where_any_is($this->_get_compound_id_column_values_array($ids)) :
-            $this->where_in($this->_get_id_column_name(), $ids);
-    }
-
-    /**
-     * Add a WHERE ... LIKE clause to your query.
-     */
-    public function where_like($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, 'LIKE', $value);
-    }
-
-    /**
-     * Add where WHERE ... NOT LIKE clause to your query.
-     */
-    public function where_not_like($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, 'NOT LIKE', $value);
-    }
-
-    /**
-     * Add a WHERE ... > clause to your query
-     */
-    public function where_gt($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '>', $value);
-    }
-
-    /**
-     * Add a WHERE ... < clause to your query
-     */
-    public function where_lt($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '<', $value);
-    }
-
-    /**
-     * Add a WHERE ... >= clause to your query
-     */
-    public function where_gte($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '>=', $value);
-    }
-
-    /**
-     * Add a WHERE ... <= clause to your query
-     */
-    public function where_lte($column_name, $value=null) {
-        return $this->_add_simple_where($column_name, '<=', $value);
-    }
-
-    /**
-     * Add a WHERE ... IN clause to your query
-     */
-    public function where_in($column_name, $values) {
-        return $this->_add_where_placeholder($column_name, 'IN', $values);
-    }
-
-    /**
-     * Add a WHERE ... NOT IN clause to your query
-     */
-    public function where_not_in($column_name, $values) {
-        return $this->_add_where_placeholder($column_name, 'NOT IN', $values);
-    }
-
-    /**
-     * Add a WHERE column IS NULL clause to your query
-     */
-    public function where_null($column_name) {
-        return $this->_add_where_no_value($column_name, "IS NULL");
-    }
-
-    /**
-     * Add a WHERE column IS NOT NULL clause to your query
-     */
-    public function where_not_null($column_name) {
-        return $this->_add_where_no_value($column_name, "IS NOT NULL");
-    }
-
-    /**
-     * Add a raw WHERE clause to the query. The clause should
-     * contain question mark placeholders, which will be bound
-     * to the parameters supplied in the second argument.
-     */
-    public function where_raw($clause, $parameters=array()) {
-        return $this->_add_where($clause, $parameters);
-    }
-
-    /**
-     * Add a LIMIT to the query
-     */
-    public function limit($limit) {
-        $this->_limit = $limit;
-        return $this;
-    }
-
-    /**
-     * Add an OFFSET to the query
-     */
-    public function offset($offset) {
-        $this->_offset = $offset;
-        return $this;
-    }
-
-    /**
-     * Add an ORDER BY clause to the query
-     */
-    protected function _add_order_by($column_name, $ordering) {
-        $column_name = $this->_quote_identifier($column_name);
-        $this->_order_by[] = "{$column_name} {$ordering}";
-        return $this;
-    }
-
-    /**
-     * Add an ORDER BY column DESC clause
-     */
-    public function order_by_desc($column_name) {
-        return $this->_add_order_by($column_name, 'DESC');
-    }
-
-    /**
-     * Add an ORDER BY column ASC clause
-     */
-    public function order_by_asc($column_name) {
-        return $this->_add_order_by($column_name, 'ASC');
-    }
-
-    /**
-     * Add an unquoted expression as an ORDER BY clause
-     */
-    public function order_by_expr($clause) {
-        $this->_order_by[] = $clause;
-        return $this;
-    }
-
-    /**
-     * Add a column to the list of columns to GROUP BY
-     */
-    public function group_by($column_name) {
-        $column_name = $this->_quote_identifier($column_name);
-        $this->_group_by[] = $column_name;
-        return $this;
-    }
-
-    /**
-     * Add an unquoted expression to the list of columns to GROUP BY
-     */
-    public function group_by_expr($expr) {
-        $this->_group_by[] = $expr;
-        return $this;
-    }
-
-    /**
-     * Add a HAVING column = value clause to your query. Each time
-     * this is called in the chain, an additional HAVING will be
-     * added, and these will be ANDed together when the final query
-     * is built.
-     *
-     * If you use an array in $column_name, a new clause will be
-     * added for each element. In this case, $value is ignored.
-     */
-    public function having($column_name, $value=null) {
-        return $this->having_equal($column_name, $value);
-    }
-
-    /**
-     * More explicitly named version of for the having() method.
-     * Can be used if preferred.
-     */
-    public function having_equal($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '=', $value);
-    }
-
-    /**
-     * Add a HAVING column != value clause to your query.
-     */
-    public function having_not_equal($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '!=', $value);
-    }
-
-    /**
-     * Special method to query the table by its primary key.
-     *
-     * If primary key is compound, only the columns that
-     * belong to they key will be used for the query
-     */
-    public function having_id_is($id) {
-        return (is_array($this->_get_id_column_name())) ?
-            $this->having($this->_get_compound_id_column_values($value)) :
-            $this->having($this->_get_id_column_name(), $id);
-    }
-
-    /**
-     * Add a HAVING ... LIKE clause to your query.
-     */
-    public function having_like($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, 'LIKE', $value);
-    }
-
-    /**
-     * Add where HAVING ... NOT LIKE clause to your query.
-     */
-    public function having_not_like($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, 'NOT LIKE', $value);
-    }
-
-    /**
-     * Add a HAVING ... > clause to your query
-     */
-    public function having_gt($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '>', $value);
-    }
-
-    /**
-     * Add a HAVING ... < clause to your query
-     */
-    public function having_lt($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '<', $value);
-    }
-
-    /**
-     * Add a HAVING ... >= clause to your query
-     */
-    public function having_gte($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '>=', $value);
-    }
-
-    /**
-     * Add a HAVING ... <= clause to your query
-     */
-    public function having_lte($column_name, $value=null) {
-        return $this->_add_simple_having($column_name, '<=', $value);
-    }
-
-    /**
-     * Add a HAVING ... IN clause to your query
-     */
-    public function having_in($column_name, $values=null) {
-        return $this->_add_having_placeholder($column_name, 'IN', $values);
-    }
-
-    /**
-     * Add a HAVING ... NOT IN clause to your query
-     */
-    public function having_not_in($column_name, $values=null) {
-        return $this->_add_having_placeholder($column_name, 'NOT IN', $values);
-    }
-
-    /**
-     * Add a HAVING column IS NULL clause to your query
-     */
-    public function having_null($column_name) {
-        return $this->_add_having_no_value($column_name, 'IS NULL');
-    }
-
-    /**
-     * Add a HAVING column IS NOT NULL clause to your query
-     */
-    public function having_not_null($column_name) {
-        return $this->_add_having_no_value($column_name, 'IS NOT NULL');
-    }
-
-    /**
-     * Add a raw HAVING clause to the query. The clause should
-     * contain question mark placeholders, which will be bound
-     * to the parameters supplied in the second argument.
-     */
-    public function having_raw($clause, $parameters=array()) {
-        return $this->_add_having($clause, $parameters);
-    }
-
-    /**
-     * Build a SELECT statement based on the clauses that have
-     * been passed to this instance by chaining method calls.
-     */
-    protected function _build_select() {
-        // If the query is raw, just set the $this->_values to be
-        // the raw query parameters and return the raw query
-        if ($this->_is_raw_query) {
-            $this->_values = $this->_raw_parameters;
-            return $this->_raw_query;
-        }
-
-        // Build and return the full SELECT statement by concatenating
-        // the results of calling each separate builder method.
-        return $this->_join_if_not_empty(" ", array(
-            $this->_build_select_start(),
-            $this->_build_join(),
-            $this->_build_where(),
-            $this->_build_group_by(),
-            $this->_build_having(),
-            $this->_build_order_by(),
-            $this->_build_limit(),
-            $this->_build_offset(),
-        ));
-    }
-
-    /**
-     * Build the start of the SELECT statement
-     */
-    protected function _build_select_start() {
-        $fragment = 'SELECT ';
-        $result_columns = join(', ', $this->_result_columns);
-
-        if (!is_null($this->_limit) &&
-            self::$_config[$this->_connection_name]['limit_clause_style'] === ORM::LIMIT_STYLE_TOP_N) {
-            $fragment .= "TOP {$this->_limit} ";
-        }
-
-        if ($this->_distinct) {
-            $result_columns = 'DISTINCT ' . $result_columns;
-        }
-
-        $fragment .= "{$result_columns} FROM " . $this->_quote_identifier($this->_table_name);
-
-        if (!is_null($this->_table_alias)) {
-            $fragment .= " " . $this->_quote_identifier($this->_table_alias);
-        }
-        return $fragment;
-    }
-
-    /**
-     * Build the JOIN sources
-     */
-    protected function _build_join() {
-        if (count($this->_join_sources) === 0) {
-            return '';
-        }
-
-        return join(" ", $this->_join_sources);
-    }
-
-    /**
-     * Build the WHERE clause(s)
-     */
-    protected function _build_where() {
-        return $this->_build_conditions('where');
-    }
-
-    /**
-     * Build the HAVING clause(s)
-     */
-    protected function _build_having() {
-        return $this->_build_conditions('having');
-    }
-
-    /**
-     * Build GROUP BY
-     */
-    protected function _build_group_by() {
-        if (count($this->_group_by) === 0) {
-            return '';
-        }
-        return "GROUP BY " . join(", ", $this->_group_by);
-    }
-
-    /**
-     * Build a WHERE or HAVING clause
-     * @param string $type
-     * @return string
-     */
-    protected function _build_conditions($type) {
-        $conditions_class_property_name = "_{$type}_conditions";
-        // If there are no clauses, return empty string
-        if (count($this->$conditions_class_property_name) === 0) {
-            return '';
-        }
-
-        $conditions = array();
-        foreach ($this->$conditions_class_property_name as $condition) {
-            $conditions[] = $condition[self::CONDITION_FRAGMENT];
-            $this->_values = array_merge($this->_values, $condition[self::CONDITION_VALUES]);
-        }
-
-        return strtoupper($type) . " " . join(" AND ", $conditions);
-    }
-
-    /**
-     * Build ORDER BY
-     */
-    protected function _build_order_by() {
-        if (count($this->_order_by) === 0) {
-            return '';
-        }
-        return "ORDER BY " . join(", ", $this->_order_by);
-    }
-
-    /**
-     * Build LIMIT
-     */
-    protected function _build_limit() {
-        $fragment = '';
-        if (!is_null($this->_limit) &&
-            self::$_config[$this->_connection_name]['limit_clause_style'] == ORM::LIMIT_STYLE_LIMIT) {
-            if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'firebird') {
-                $fragment = 'ROWS';
-            } else {
-                $fragment = 'LIMIT';
-            }
-            $fragment .= " {$this->_limit}";
-        }
-        return $fragment;
-    }
-
-    /**
-     * Build OFFSET
-     */
-    protected function _build_offset() {
-        if (!is_null($this->_offset)) {
-            $clause = 'OFFSET';
-            if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'firebird') {
-                $clause = 'TO';
-            }
-            return "$clause " . $this->_offset;
-        }
-        return '';
-    }
-
-    /**
-     * Wrapper around PHP's join function which
-     * only adds the pieces if they are not empty.
-     */
-    protected function _join_if_not_empty($glue, $pieces) {
-        $filtered_pieces = array();
-        foreach ($pieces as $piece) {
-            if (is_string($piece)) {
-                $piece = trim($piece);
-            }
-            if (!empty($piece)) {
-                $filtered_pieces[] = $piece;
-            }
-        }
-        return join($glue, $filtered_pieces);
-    }
-
-    /**
-     * Quote a string that is used as an identifier
-     * (table names, column names etc). This method can
-     * also deal with dot-separated identifiers eg table.column
-     */
-    protected function _quote_one_identifier($identifier) {
-        $parts = explode('.', $identifier);
-        $parts = array_map(array($this, '_quote_identifier_part'), $parts);
-        return join('.', $parts);
-    }
-
-    /**
-     * Quote a string that is used as an identifier
-     * (table names, column names etc) or an array containing
-     * multiple identifiers. This method can also deal with
-     * dot-separated identifiers eg table.column
-     */
-    protected function _quote_identifier($identifier) {
-        if (is_array($identifier)) {
-            $result = array_map(array($this, '_quote_one_identifier'), $identifier);
-            return join(', ', $result);
-        } else {
-            return $this->_quote_one_identifier($identifier);
-        }
-    }
-
-    /**
-     * This method performs the actual quoting of a single
-     * part of an identifier, using the identifier quote
-     * character specified in the config (or autodetected).
-     */
-    protected function _quote_identifier_part($part) {
-        if ($part === '*') {
-            return $part;
-        }
-
-        $quote_character = self::$_config[$this->_connection_name]['identifier_quote_character'];
-        // double up any identifier quotes to escape them
-        return $quote_character .
-        str_replace($quote_character,
-            $quote_character . $quote_character,
-            $part
-        ) . $quote_character;
-    }
-
-    /**
-     * Create a cache key for the given query and parameters.
-     */
-    protected static function _create_cache_key($query, $parameters, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
-        if(isset(self::$_config[$connection_name]['create_cache_key']) and is_callable(self::$_config[$connection_name]['create_cache_key'])){
-            return call_user_func_array(self::$_config[$connection_name]['create_cache_key'], array($query, $parameters, $table_name, $connection_name));
-        }
-        $parameter_string = join(',', $parameters);
-        $key = $query . ':' . $parameter_string;
-        return sha1($key);
-    }
-
-    /**
-     * Check the query cache for the given cache key. If a value
-     * is cached for the key, return the value. Otherwise, return false.
-     */
-    protected static function _check_query_cache($cache_key, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
-        if(isset(self::$_config[$connection_name]['check_query_cache']) and is_callable(self::$_config[$connection_name]['check_query_cache'])){
-            return call_user_func_array(self::$_config[$connection_name]['check_query_cache'], array($cache_key, $table_name, $connection_name));
-        } elseif (isset(self::$_query_cache[$connection_name][$cache_key])) {
-            return self::$_query_cache[$connection_name][$cache_key];
-        }
-        return false;
-    }
-
-    /**
-     * Clear the query cache
-     */
-    public static function clear_cache($table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
-        self::$_query_cache = array();
-        if(isset(self::$_config[$connection_name]['clear_cache']) and is_callable(self::$_config[$connection_name]['clear_cache'])){
-            return call_user_func_array(self::$_config[$connection_name]['clear_cache'], array($table_name, $connection_name));
-        }
-    }
-
-    /**
-     * Add the given value to the query cache.
-     */
-    protected static function _cache_query_result($cache_key, $value, $table_name = null, $connection_name = self::DEFAULT_CONNECTION) {
-        if(isset(self::$_config[$connection_name]['cache_query_result']) and is_callable(self::$_config[$connection_name]['cache_query_result'])){
-            return call_user_func_array(self::$_config[$connection_name]['cache_query_result'], array($cache_key, $value, $table_name, $connection_name));
-        } elseif (!isset(self::$_query_cache[$connection_name])) {
-            self::$_query_cache[$connection_name] = array();
-        }
-        self::$_query_cache[$connection_name][$cache_key] = $value;
-    }
-
-    /**
-     * Execute the SELECT query that has been built up by chaining methods
-     * on this class. Return an array of rows as associative arrays.
-     */
-    protected function _run() {
-        $query = $this->_build_select();
-        $caching_enabled = self::$_config[$this->_connection_name]['caching'];
-
-        if ($caching_enabled) {
-            $cache_key = self::_create_cache_key($query, $this->_values, $this->_table_name, $this->_connection_name);
-            $cached_result = self::_check_query_cache($cache_key, $this->_table_name, $this->_connection_name);
-
-            if ($cached_result !== false) {
-                return $cached_result;
+                $query[] = "= ?";
             }
         }
 
-        self::_execute($query, $this->_values, $this->_connection_name);
-        $statement = self::get_last_statement();
+        /**
+         * Build an UPDATE query
+         */
+        protected function _build_update() {
+            $query = array();
+            $query[] = "UPDATE {$this->_quote_identifier($this->_table_name)} SET";
 
-        $rows = array();
-        while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
-            $rows[] = $row;
-        }
-
-        if ($caching_enabled) {
-            self::_cache_query_result($cache_key, $rows, $this->_table_name, $this->_connection_name);
-        }
-
-        // reset Idiorm after executing the query
-        $this->_values = array();
-        $this->_result_columns = array('*');
-        $this->_using_default_result_columns = true;
-
-        return $rows;
-    }
-
-    /**
-     * Return the raw data wrapped by this ORM
-     * instance as an associative array. Column
-     * names may optionally be supplied as arguments,
-     * if so, only those keys will be returned.
-     */
-    public function as_array() {
-        if (func_num_args() === 0) {
-            return $this->_data;
-        }
-        $args = func_get_args();
-        return array_intersect_key($this->_data, array_flip($args));
-    }
-
-    /**
-     * Return the value of a property of this object (database row)
-     * or null if not present.
-     *
-     * If a column-names array is passed, it will return a associative array
-     * with the value of each column or null if it is not present.
-     */
-    public function get($key) {
-        if (is_array($key)) {
-            $result = array();
-            foreach($key as $column) {
-                $result[$column] = isset($this->_data[$column]) ? $this->_data[$column] : null;
-            }
-            return $result;
-        } else {
-            return isset($this->_data[$key]) ? $this->_data[$key] : null;
-        }
-    }
-
-    /**
-     * Return the name of the column in the database table which contains
-     * the primary key ID of the row.
-     */
-    protected function _get_id_column_name() {
-        if (!is_null($this->_instance_id_column)) {
-            return $this->_instance_id_column;
-        }
-        if (isset(self::$_config[$this->_connection_name]['id_column_overrides'][$this->_table_name])) {
-            return self::$_config[$this->_connection_name]['id_column_overrides'][$this->_table_name];
-        }
-        return self::$_config[$this->_connection_name]['id_column'];
-    }
-
-    /**
-     * Get the primary key ID of this object.
-     */
-    public function id($disallow_null = false) {
-        $id = $this->get($this->_get_id_column_name());
-
-        if ($disallow_null) {
-            if (is_array($id)) {
-                foreach ($id as $id_part) {
-                    if ($id_part === null) {
-                        throw new Exception('Primary key ID contains null value(s)');
-                    }
+            $field_list = array();
+            foreach ($this->_dirty_fields as $key => $value) {
+                if(!array_key_exists($key, $this->_expr_fields)) {
+                    $value = '?';
                 }
-            } else if ($id === null) {
-                throw new Exception('Primary key ID missing from row or is null');
+                $field_list[] = "{$this->_quote_identifier($key)} = $value";
             }
+            $query[] = join(", ", $field_list);
+            $this->_add_id_column_conditions($query);
+            return join(" ", $query);
         }
 
-        return $id;
-    }
+        /**
+         * Build an INSERT query
+         */
+        protected function _build_insert() {
+            $query[] = "INSERT INTO";
+            $query[] = $this->_quote_identifier($this->_table_name);
+            $field_list = array_map(array($this, '_quote_identifier'), array_keys($this->_dirty_fields));
+            $query[] = "(" . join(", ", $field_list) . ")";
+            $query[] = "VALUES";
 
-    /**
-     * Set a property to a particular value on this object.
-     * To set multiple properties at once, pass an associative array
-     * as the first parameter and leave out the second parameter.
-     * Flags the properties as 'dirty' so they will be saved to the
-     * database when save() is called.
-     */
-    public function set($key, $value = null) {
-        return $this->_set_orm_property($key, $value);
-    }
+            $placeholders = $this->_create_placeholders($this->_dirty_fields);
+            $query[] = "({$placeholders})";
 
-    /**
-     * Set a property to a particular value on this object.
-     * To set multiple properties at once, pass an associative array
-     * as the first parameter and leave out the second parameter.
-     * Flags the properties as 'dirty' so they will be saved to the
-     * database when save() is called.
-     * @param string|array $key
-     * @param string|null $value
-     */
-    public function set_expr($key, $value = null) {
-        return $this->_set_orm_property($key, $value, true);
-    }
-
-    /**
-     * Set a property on the ORM object.
-     * @param string|array $key
-     * @param string|null $value
-     * @param bool $raw Whether this value should be treated as raw or not
-     */
-    protected function _set_orm_property($key, $value = null, $expr = false) {
-        if (!is_array($key)) {
-            $key = array($key => $value);
-        }
-        foreach ($key as $field => $value) {
-            $this->_data[$field] = $value;
-            $this->_dirty_fields[$field] = $value;
-            if (false === $expr and isset($this->_expr_fields[$field])) {
-                unset($this->_expr_fields[$field]);
-            } else if (true === $expr) {
-                $this->_expr_fields[$field] = true;
+            if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'pgsql') {
+                $query[] = 'RETURNING ' . $this->_quote_identifier($this->_get_id_column_name());
             }
+
+            return join(" ", $query);
         }
-        return $this;
-    }
 
-    /**
-     * Check whether the given field has been changed since this
-     * object was saved.
-     */
-    public function is_dirty($key) {
-        return isset($this->_dirty_fields[$key]);
-    }
+        /**
+         * Delete this record from the database
+         */
+        public function delete() {
+            $query = array(
+                "DELETE FROM",
+                $this->_quote_identifier($this->_table_name)
+            );
+            $this->_add_id_column_conditions($query);
+            return self::_execute(join(" ", $query), is_array($this->id(true)) ? array_values($this->id(true)) : array($this->id(true)), $this->_connection_name);
+        }
 
-    /**
-     * Check whether the model was the result of a call to create() or not
-     * @return bool
-     */
-    public function is_new() {
-        return $this->_is_new;
-    }
+        /**
+         * Delete many records from the database
+         */
+        public function delete_many() {
+            // Build and return the full DELETE statement by concatenating
+            // the results of calling each separate builder method.
+            $query = $this->_join_if_not_empty(" ", array(
+                "DELETE FROM",
+                $this->_quote_identifier($this->_table_name),
+                $this->_build_where(),
+            ));
 
-    /**
-     * Save any fields which have been modified on this object
-     * to the database.
-     */
-    public function save() {
-        $query = array();
+            return self::_execute($query, $this->_values, $this->_connection_name);
+        }
 
-        // remove any expression fields as they are already baked into the query
-        $values = array_values(array_diff_key($this->_dirty_fields, $this->_expr_fields));
+        // --------------------- //
+        // ---  ArrayAccess  --- //
+        // --------------------- //
 
-        if (!$this->_is_new) { // UPDATE
-            // If there are no dirty values, do nothing
-            if (empty($values) && empty($this->_expr_fields)) {
-                return true;
+        #[\ReturnTypeWillChange]
+        public function offsetExists($key) {
+            return array_key_exists($key, $this->_data);
+        }
+
+        #[\ReturnTypeWillChange]
+        public function offsetGet($key) {
+            return $this->get($key);
+        }
+
+        #[\ReturnTypeWillChange]
+        public function offsetSet($key, $value) {
+            if(is_null($key)) {
+                throw new InvalidArgumentException('You must specify a key/array index.');
             }
-            $query = $this->_build_update();
-            $id = $this->id(true);
-            if (is_array($id)) {
-                $values = array_merge($values, array_values($id));
+            $this->set($key, $value);
+        }
+
+        #[\ReturnTypeWillChange]
+        public function offsetUnset($key) {
+            unset($this->_data[$key]);
+            unset($this->_dirty_fields[$key]);
+        }
+
+        // --------------------- //
+        // --- MAGIC METHODS --- //
+        // --------------------- //
+        public function __get($key) {
+            return $this->offsetGet($key);
+        }
+
+        public function __set($key, $value) {
+            $this->offsetSet($key, $value);
+        }
+
+        public function __unset($key) {
+            $this->offsetUnset($key);
+        }
+
+
+        public function __isset($key) {
+            return $this->offsetExists($key);
+        }
+
+        /**
+         * Magic method to capture calls to undefined class methods.
+         * In this case we are attempting to convert camel case formatted
+         * methods into underscore formatted methods.
+         *
+         * This allows us to call ORM methods using camel case and remain
+         * backwards compatible.
+         *
+         * @param  string   $name
+         * @param  array    $arguments
+         * @return ORM
+         */
+        public function __call($name, $arguments)
+        {
+            $method = strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', $name));
+
+            if (method_exists($this, $method)) {
+                return call_user_func_array(array($this, $method), $arguments);
             } else {
-                $values[] = $id;
-            }
-        } else { // INSERT
-            $query = $this->_build_insert();
-        }
-
-        $success = self::_execute($query, $values, $this->_connection_name);
-        $caching_auto_clear_enabled = self::$_config[$this->_connection_name]['caching_auto_clear'];
-        if($caching_auto_clear_enabled){
-            self::clear_cache($this->_table_name, $this->_connection_name);
-        }
-        // If we've just inserted a new record, set the ID of this object
-        if ($this->_is_new) {
-            $this->_is_new = false;
-            if ($this->count_null_id_columns() != 0) {
-                $db = self::get_db($this->_connection_name);
-                if($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'pgsql') {
-                    // it may return several columns if a compound primary
-                    // key is used
-                    $row = self::get_last_statement()->fetch(PDO::FETCH_ASSOC);
-                    foreach($row as $key => $value) {
-                        $this->_data[$key] = $value;
-                    }
-                } else {
-                    $column = $this->_get_id_column_name();
-                    // if the primary key is compound, assign the last inserted id
-                    // to the first column
-                    if (is_array($column)) {
-                        $column = array_slice($column, 0, 1);
-                    }
-                    $this->_data[$column] = $db->lastInsertId();
-                }
+                throw new IdiormMethodMissingException("Method $name() does not exist in class " . get_class($this));
             }
         }
 
-        $this->_dirty_fields = $this->_expr_fields = array();
-        return $success;
-    }
+        /**
+         * Magic method to capture calls to undefined static class methods.
+         * In this case we are attempting to convert camel case formatted
+         * methods into underscore formatted methods.
+         *
+         * This allows us to call ORM methods using camel case and remain
+         * backwards compatible.
+         *
+         * @param  string   $name
+         * @param  array    $arguments
+         * @return ORM
+         */
+        public static function __callStatic($name, $arguments)
+        {
+            $method = strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', $name));
 
-    /**
-     * Add a WHERE clause for every column that belongs to the primary key
-     */
-    public function _add_id_column_conditions(&$query) {
-        $query[] = "WHERE";
-        $keys = is_array($this->_get_id_column_name()) ? $this->_get_id_column_name() : array( $this->_get_id_column_name() );
-        $first = true;
-        foreach($keys as $key) {
-            if ($first) {
-                $first = false;
-            }
-            else {
-                $query[] = "AND";
-            }
-            $query[] = $this->_quote_identifier($key);
-            $query[] = "= ?";
+            return call_user_func_array(array('ORM', $method), $arguments);
         }
     }
 
     /**
-     * Build an UPDATE query
-     */
-    protected function _build_update() {
-        $query = array();
-        $query[] = "UPDATE {$this->_quote_identifier($this->_table_name)} SET";
-
-        $field_list = array();
-        foreach ($this->_dirty_fields as $key => $value) {
-            if(!array_key_exists($key, $this->_expr_fields)) {
-                $value = '?';
-            }
-            $field_list[] = "{$this->_quote_identifier($key)} = $value";
-        }
-        $query[] = join(", ", $field_list);
-        $this->_add_id_column_conditions($query);
-        return join(" ", $query);
-    }
-
-    /**
-     * Build an INSERT query
-     */
-    protected function _build_insert() {
-        $query[] = "INSERT INTO";
-        $query[] = $this->_quote_identifier($this->_table_name);
-        $field_list = array_map(array($this, '_quote_identifier'), array_keys($this->_dirty_fields));
-        $query[] = "(" . join(", ", $field_list) . ")";
-        $query[] = "VALUES";
-
-        $placeholders = $this->_create_placeholders($this->_dirty_fields);
-        $query[] = "({$placeholders})";
-
-        if (self::get_db($this->_connection_name)->getAttribute(PDO::ATTR_DRIVER_NAME) == 'pgsql') {
-            $query[] = 'RETURNING ' . $this->_quote_identifier($this->_get_id_column_name());
-        }
-
-        return join(" ", $query);
-    }
-
-    /**
-     * Delete this record from the database
-     */
-    public function delete() {
-        $query = array(
-            "DELETE FROM",
-            $this->_quote_identifier($this->_table_name)
-        );
-        $this->_add_id_column_conditions($query);
-        return self::_execute(join(" ", $query), is_array($this->id(true)) ? array_values($this->id(true)) : array($this->id(true)), $this->_connection_name);
-    }
-
-    /**
-     * Delete many records from the database
-     */
-    public function delete_many() {
-        // Build and return the full DELETE statement by concatenating
-        // the results of calling each separate builder method.
-        $query = $this->_join_if_not_empty(" ", array(
-            "DELETE FROM",
-            $this->_quote_identifier($this->_table_name),
-            $this->_build_where(),
-        ));
-
-        return self::_execute($query, $this->_values, $this->_connection_name);
-    }
-
-    // --------------------- //
-    // ---  ArrayAccess  --- //
-    // --------------------- //
-
-    public function offsetExists($key) {
-        return array_key_exists($key, $this->_data);
-    }
-
-    public function offsetGet($key) {
-        return $this->get($key);
-    }
-
-    public function offsetSet($key, $value) {
-        if(is_null($key)) {
-            throw new InvalidArgumentException('You must specify a key/array index.');
-        }
-        $this->set($key, $value);
-    }
-
-    public function offsetUnset($key) {
-        unset($this->_data[$key]);
-        unset($this->_dirty_fields[$key]);
-    }
-
-    // --------------------- //
-    // --- MAGIC METHODS --- //
-    // --------------------- //
-    public function __get($key) {
-        return $this->offsetGet($key);
-    }
-
-    public function __set($key, $value) {
-        $this->offsetSet($key, $value);
-    }
-
-    public function __unset($key) {
-        $this->offsetUnset($key);
-    }
-
-
-    public function __isset($key) {
-        return $this->offsetExists($key);
-    }
-
-    /**
-     * Magic method to capture calls to undefined class methods.
-     * In this case we are attempting to convert camel case formatted
-     * methods into underscore formatted methods.
-     *
-     * This allows us to call ORM methods using camel case and remain
-     * backwards compatible.
-     *
-     * @param  string   $name
-     * @param  array    $arguments
-     * @return ORM
-     */
-    public function __call($name, $arguments)
-    {
-        $method = strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', $name));
-
-        if (method_exists($this, $method)) {
-            return call_user_func_array(array($this, $method), $arguments);
-        } else {
-            throw new IdiormMethodMissingException("Method $name() does not exist in class " . get_class($this));
-        }
-    }
-
-    /**
-     * Magic method to capture calls to undefined static class methods.
-     * In this case we are attempting to convert camel case formatted
-     * methods into underscore formatted methods.
-     *
-     * This allows us to call ORM methods using camel case and remain
-     * backwards compatible.
-     *
-     * @param  string   $name
-     * @param  array    $arguments
-     * @return ORM
-     */
-    public static function __callStatic($name, $arguments)
-    {
-        $method = strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', $name));
-
-        return call_user_func_array(array('ORM', $method), $arguments);
-    }
-}
-
-/**
- * A class to handle str_replace operations that involve quoted strings
- * @example IdiormString::str_replace_outside_quotes('?', '%s', 'columnA = "Hello?" AND columnB = ?');
- * @example IdiormString::value('columnA = "Hello?" AND columnB = ?')->replace_outside_quotes('?', '%s');
- * @author Jeff Roberson <ridgerunner@fluxbb.org>
- * @author Simon Holywell <treffynnon@php.net>
- * @link http://stackoverflow.com/a/13370709/461813 StackOverflow answer
- */
-class IdiormString {
-    protected $subject;
-    protected $search;
-    protected $replace;
-
-    /**
-     * Get an easy to use instance of the class
-     * @param string $subject
-     * @return \self
-     */
-    public static function value($subject) {
-        return new self($subject);
-    }
-
-    /**
-     * Shortcut method: Replace all occurrences of the search string with the replacement
-     * string where they appear outside quotes.
-     * @param string $search
-     * @param string $replace
-     * @param string $subject
-     * @return string
-     */
-    public static function str_replace_outside_quotes($search, $replace, $subject) {
-        return self::value($subject)->replace_outside_quotes($search, $replace);
-    }
-
-    /**
-     * Set the base string object
-     * @param string $subject
-     */
-    public function __construct($subject) {
-        $this->subject = (string) $subject;
-    }
-
-    /**
-     * Replace all occurrences of the search string with the replacement
-     * string where they appear outside quotes
-     * @param string $search
-     * @param string $replace
-     * @return string
-     */
-    public function replace_outside_quotes($search, $replace) {
-        $this->search = $search;
-        $this->replace = $replace;
-        return $this->_str_replace_outside_quotes();
-    }
-
-    /**
-     * Validate an input string and perform a replace on all ocurrences
-     * of $this->search with $this->replace
+     * A class to handle str_replace operations that involve quoted strings
+     * @example IdiormString::str_replace_outside_quotes('?', '%s', 'columnA = "Hello?" AND columnB = ?');
+     * @example IdiormString::value('columnA = "Hello?" AND columnB = ?')->replace_outside_quotes('?', '%s');
      * @author Jeff Roberson <ridgerunner@fluxbb.org>
+     * @author Simon Holywell <treffynnon@php.net>
      * @link http://stackoverflow.com/a/13370709/461813 StackOverflow answer
-     * @return string
      */
-    protected function _str_replace_outside_quotes(){
-        $re_valid = '/
+    class IdiormString {
+        protected $subject;
+        protected $search;
+        protected $replace;
+
+        /**
+         * Get an easy to use instance of the class
+         * @param string $subject
+         * @return \self
+         */
+        public static function value($subject) {
+            return new self($subject);
+        }
+
+        /**
+         * Shortcut method: Replace all occurrences of the search string with the replacement
+         * string where they appear outside quotes.
+         * @param string $search
+         * @param string $replace
+         * @param string $subject
+         * @return string
+         */
+        public static function str_replace_outside_quotes($search, $replace, $subject) {
+            return self::value($subject)->replace_outside_quotes($search, $replace);
+        }
+
+        /**
+         * Set the base string object
+         * @param string $subject
+         */
+        public function __construct($subject) {
+            $this->subject = (string) $subject;
+        }
+
+        /**
+         * Replace all occurrences of the search string with the replacement
+         * string where they appear outside quotes
+         * @param string $search
+         * @param string $replace
+         * @return string
+         */
+        public function replace_outside_quotes($search, $replace) {
+            $this->search = $search;
+            $this->replace = $replace;
+            return $this->_str_replace_outside_quotes();
+        }
+
+        /**
+         * Validate an input string and perform a replace on all ocurrences
+         * of $this->search with $this->replace
+         * @author Jeff Roberson <ridgerunner@fluxbb.org>
+         * @link http://stackoverflow.com/a/13370709/461813 StackOverflow answer
+         * @return string
+         */
+        protected function _str_replace_outside_quotes(){
+            $re_valid = '/
                 # Validate string having embedded quoted substrings.
                 ^                           # Anchor to start of string.
                 (?:                         # Zero or more string chunks.
@@ -2285,10 +2369,10 @@ class IdiormString {
                 )*                          # Zero or more string chunks.
                 \z                          # Anchor to end of string.
                 /sx';
-        if (!preg_match($re_valid, $this->subject)) {
-            throw new IdiormStringException("Subject string is not valid in the replace_outside_quotes context.");
-        }
-        $re_parse = '/
+            if (!preg_match($re_valid, $this->subject)) {
+                throw new IdiormStringException("Subject string is not valid in the replace_outside_quotes context.");
+            }
+            $re_parse = '/
                 # Match one chunk of a valid string having embedded quoted substrings.
                   (                         # Either $1: Quoted chunk.
                     "[^"\\\\]*(?:\\\\.[^"\\\\]*)*"  # Either a double quoted chunk,
@@ -2296,162 +2380,178 @@ class IdiormString {
                   )                         # End $1: Quoted chunk.
                 | ([^\'"\\\\]+)             # or $2: an unquoted chunk (no escapes).
                 /sx';
-        return preg_replace_callback($re_parse, array($this, '_str_replace_outside_quotes_cb'), $this->subject);
-    }
-
-    /**
-     * Process each matching chunk from preg_replace_callback replacing
-     * each occurrence of $this->search with $this->replace
-     * @author Jeff Roberson <ridgerunner@fluxbb.org>
-     * @link http://stackoverflow.com/a/13370709/461813 StackOverflow answer
-     * @param array $matches
-     * @return string
-     */
-    protected function _str_replace_outside_quotes_cb($matches) {
-        // Return quoted string chunks (in group $1) unaltered.
-        if ($matches[1]) return $matches[1];
-        // Process only unquoted chunks (in group $2).
-        return preg_replace('/'. preg_quote($this->search, '/') .'/',
-            $this->replace, $matches[2]);
-    }
-}
-
-/**
- * A result set class for working with collections of model instances
- * @author Simon Holywell <treffynnon@php.net>
- */
-class IdiormResultSet implements Countable, IteratorAggregate, ArrayAccess, Serializable {
-    /**
-     * The current result set as an array
-     * @var array
-     */
-    protected $_results = array();
-
-    /**
-     * Optionally set the contents of the result set by passing in array
-     * @param array $results
-     */
-    public function __construct(array $results = array()) {
-        $this->set_results($results);
-    }
-
-    /**
-     * Set the contents of the result set by passing in array
-     * @param array $results
-     */
-    public function set_results(array $results) {
-        $this->_results = $results;
-    }
-
-    /**
-     * Get the current result set as an array
-     * @return array
-     */
-    public function get_results() {
-        return $this->_results;
-    }
-
-    /**
-     * Get the current result set as an array
-     * @return array
-     */
-    public function as_array() {
-        return $this->get_results();
-    }
-
-    /**
-     * Get the number of records in the result set
-     * @return int
-     */
-    public function count() {
-        return count($this->_results);
-    }
-
-    /**
-     * Get an iterator for this object. In this case it supports foreaching
-     * over the result set.
-     * @return \ArrayIterator
-     */
-    public function getIterator() {
-        return new ArrayIterator($this->_results);
-    }
-
-    /**
-     * ArrayAccess
-     * @param int|string $offset
-     * @return bool
-     */
-    public function offsetExists($offset) {
-        return isset($this->_results[$offset]);
-    }
-
-    /**
-     * ArrayAccess
-     * @param int|string $offset
-     * @return mixed
-     */
-    public function offsetGet($offset) {
-        return $this->_results[$offset];
-    }
-
-    /**
-     * ArrayAccess
-     * @param int|string $offset
-     * @param mixed $value
-     */
-    public function offsetSet($offset, $value) {
-        $this->_results[$offset] = $value;
-    }
-
-    /**
-     * ArrayAccess
-     * @param int|string $offset
-     */
-    public function offsetUnset($offset) {
-        unset($this->_results[$offset]);
-    }
-
-    /**
-     * Serializable
-     * @return string
-     */
-    public function serialize() {
-        return serialize($this->_results);
-    }
-
-    /**
-     * Serializable
-     * @param string $serialized
-     * @return array
-     */
-    public function unserialize($serialized) {
-        return unserialize($serialized);
-    }
-
-    /**
-     * Call a method on all models in a result set. This allows for method
-     * chaining such as setting a property on all models in a result set or
-     * any other batch operation across models.
-     * @example ORM::for_table('Widget')->find_many()->set('field', 'value')->save();
-     * @param string $method
-     * @param array $params
-     * @return \IdiormResultSet
-     */
-    public function __call($method, $params = array()) {
-        foreach($this->_results as $model) {
-            if (method_exists($model, $method)) {
-                call_user_func_array(array($model, $method), $params);
-            } else {
-                throw new IdiormMethodMissingException("Method $method() does not exist in class " . get_class($this));
-            }
+            return preg_replace_callback($re_parse, array($this, '_str_replace_outside_quotes_cb'), $this->subject);
+        }
+
+        /**
+         * Process each matching chunk from preg_replace_callback replacing
+         * each occurrence of $this->search with $this->replace
+         * @author Jeff Roberson <ridgerunner@fluxbb.org>
+         * @link http://stackoverflow.com/a/13370709/461813 StackOverflow answer
+         * @param array $matches
+         * @return string
+         */
+        protected function _str_replace_outside_quotes_cb($matches) {
+            // Return quoted string chunks (in group $1) unaltered.
+            if ($matches[1]) return $matches[1];
+            // Process only unquoted chunks (in group $2).
+            return preg_replace('/'. preg_quote($this->search, '/') .'/',
+                $this->replace, $matches[2]);
         }
-        return $this;
     }
-}
 
-/**
- * A placeholder for exceptions eminating from the IdiormString class
- */
-class IdiormStringException extends Exception {}
+    /**
+     * A result set class for working with collections of model instances
+     * @author Simon Holywell <treffynnon@php.net>
+     * @method null setResults(array $results)
+     * @method array getResults()
+     */
+    class IdiormResultSet implements Countable, IteratorAggregate, ArrayAccess, Serializable {
+        /**
+         * The current result set as an array
+         * @var array
+         */
+        protected $_results = array();
 
-class IdiormMethodMissingException extends Exception {}
\ No newline at end of file
+        /**
+         * Optionally set the contents of the result set by passing in array
+         * @param array $results
+         */
+        public function __construct(array $results = array()) {
+            $this->set_results($results);
+        }
+
+        /**
+         * Set the contents of the result set by passing in array
+         * @param array $results
+         */
+        public function set_results(array $results) {
+            $this->_results = $results;
+        }
+
+        /**
+         * Get the current result set as an array
+         * @return array
+         */
+        public function get_results() {
+            return $this->_results;
+        }
+
+        /**
+         * Get the current result set as an array
+         * @return array
+         */
+        public function as_array() {
+            return $this->get_results();
+        }
+
+        /**
+         * Get the number of records in the result set
+         * @return int
+         */
+        #[\ReturnTypeWillChange]
+        public function count() {
+            return count($this->_results);
+        }
+
+        /**
+         * Get an iterator for this object. In this case it supports foreaching
+         * over the result set.
+         * @return \ArrayIterator
+         */
+        #[\ReturnTypeWillChange]
+        public function getIterator() {
+            return new ArrayIterator($this->_results);
+        }
+
+        /**
+         * ArrayAccess
+         * @param int|string $offset
+         * @return bool
+         */
+        #[\ReturnTypeWillChange]
+        public function offsetExists($offset) {
+            return isset($this->_results[$offset]);
+        }
+
+        /**
+         * ArrayAccess
+         * @param int|string $offset
+         * @return mixed
+         */
+        #[\ReturnTypeWillChange]
+        public function offsetGet($offset) {
+            return $this->_results[$offset];
+        }
+
+        /**
+         * ArrayAccess
+         * @param int|string $offset
+         * @param mixed $value
+         */
+        #[\ReturnTypeWillChange]
+        public function offsetSet($offset, $value) {
+            $this->_results[$offset] = $value;
+        }
+
+        /**
+         * ArrayAccess
+         * @param int|string $offset
+         */
+        #[\ReturnTypeWillChange]
+        public function offsetUnset($offset) {
+            unset($this->_results[$offset]);
+        }
+
+        public function __serialize() {
+            return $this->serialize();
+        }
+
+        public function __unserialize($data) {
+            $this->unserialize($data);
+        }
+
+        /**
+         * Serializable
+         * @return string
+         */
+        public function serialize() {
+            return serialize($this->_results);
+        }
+
+        /**
+         * Serializable
+         * @param string $serialized
+         * @return array
+         */
+        public function unserialize($serialized) {
+            return unserialize($serialized);
+        }
+
+        /**
+         * Call a method on all models in a result set. This allows for method
+         * chaining such as setting a property on all models in a result set or
+         * any other batch operation across models.
+         * @example ORM::for_table('Widget')->find_many()->set('field', 'value')->save();
+         * @param string $method
+         * @param array $params
+         * @return \IdiormResultSet
+         */
+        public function __call($method, $params = array()) {
+            foreach($this->_results as $model) {
+                if (method_exists($model, $method)) {
+                    call_user_func_array(array($model, $method), $params);
+                } else {
+                    throw new IdiormMethodMissingException("Method $method() does not exist in class " . get_class($this));
+                }
+            }
+            return $this;
+        }
+    }
+
+    /**
+     * A placeholder for exceptions eminating from the IdiormString class
+     */
+    class IdiormStringException extends Exception {}
+
+    class IdiormMethodMissingException extends Exception {}