Merge tag '3.1.5' into dev-ci3

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 2805 insertions, 0 deletions

diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
new file mode 100644
index 000000000..9216651aa
--- /dev/null
+++ b/system/database/DB_query_builder.php
@@ -0,0 +1,2805 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP
+ *
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	https://codeigniter.com
+ * @since	Version 1.0.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * Query Builder Class
+ *
+ * This is the platform-independent base Query Builder implementation class.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Drivers
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		https://codeigniter.com/user_guide/database/
+ */
+
+abstract class CI_DB_query_builder extends CI_DB_driver {
+
+	/**
+	 * Return DELETE SQL flag
+	 *
+	 * @var	bool
+	 */
+	protected $return_delete_sql		= FALSE;
+
+	/**
+	 * Reset DELETE data flag
+	 *
+	 * @var	bool
+	 */
+	protected $reset_delete_data		= FALSE;
+
+	/**
+	 * QB SELECT data
+	 *
+	 * @var	array
+	 */
+	protected $qb_select			= array();
+
+	/**
+	 * QB DISTINCT flag
+	 *
+	 * @var	bool
+	 */
+	protected $qb_distinct			= FALSE;
+
+	/**
+	 * QB FROM data
+	 *
+	 * @var	array
+	 */
+	protected $qb_from			= array();
+
+	/**
+	 * QB JOIN data
+	 *
+	 * @var	array
+	 */
+	protected $qb_join			= array();
+
+	/**
+	 * QB WHERE data
+	 *
+	 * @var	array
+	 */
+	protected $qb_where			= array();
+
+	/**
+	 * QB GROUP BY data
+	 *
+	 * @var	array
+	 */
+	protected $qb_groupby			= array();
+
+	/**
+	 * QB HAVING data
+	 *
+	 * @var	array
+	 */
+	protected $qb_having			= array();
+
+	/**
+	 * QB keys
+	 *
+	 * @var	array
+	 */
+	protected $qb_keys			= array();
+
+	/**
+	 * QB LIMIT data
+	 *
+	 * @var	int
+	 */
+	protected $qb_limit			= FALSE;
+
+	/**
+	 * QB OFFSET data
+	 *
+	 * @var	int
+	 */
+	protected $qb_offset			= FALSE;
+
+	/**
+	 * QB ORDER BY data
+	 *
+	 * @var	array
+	 */
+	protected $qb_orderby			= array();
+
+	/**
+	 * QB data sets
+	 *
+	 * @var	array
+	 */
+	protected $qb_set			= array();
+
+	/**
+	 * QB data set for update_batch()
+	 *
+	 * @var	array
+	 */
+	protected $qb_set_ub			= array();
+
+	/**
+	 * QB aliased tables list
+	 *
+	 * @var	array
+	 */
+	protected $qb_aliased_tables		= array();
+
+	/**
+	 * QB WHERE group started flag
+	 *
+	 * @var	bool
+	 */
+	protected $qb_where_group_started	= FALSE;
+
+	/**
+	 * QB WHERE group count
+	 *
+	 * @var	int
+	 */
+	protected $qb_where_group_count		= 0;
+
+	// Query Builder Caching variables
+
+	/**
+	 * QB Caching flag
+	 *
+	 * @var	bool
+	 */
+	protected $qb_caching				= FALSE;
+
+	/**
+	 * QB Cache exists list
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_exists			= array();
+
+	/**
+	 * QB Cache SELECT data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_select			= array();
+
+	/**
+	 * QB Cache FROM data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_from			= array();
+
+	/**
+	 * QB Cache JOIN data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_join			= array();
+
+	/**
+	 * QB Cache aliased tables list
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_aliased_tables			= array();
+
+	/**
+	 * QB Cache WHERE data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_where			= array();
+
+	/**
+	 * QB Cache GROUP BY data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_groupby			= array();
+
+	/**
+	 * QB Cache HAVING data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_having			= array();
+
+	/**
+	 * QB Cache ORDER BY data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_orderby			= array();
+
+	/**
+	 * QB Cache data sets
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_set				= array();
+
+	/**
+	 * QB No Escape data
+	 *
+	 * @var	array
+	 */
+	protected $qb_no_escape 			= array();
+
+	/**
+	 * QB Cache No Escape data
+	 *
+	 * @var	array
+	 */
+	protected $qb_cache_no_escape			= array();
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select
+	 *
+	 * Generates the SELECT portion of the query
+	 *
+	 * @param	string
+	 * @param	mixed
+	 * @return	CI_DB_query_builder
+	 */
+	public function select($select = '*', $escape = NULL)
+	{
+		if (is_string($select))
+		{
+			$select = explode(',', $select);
+		}
+
+		// If the escape value was not set, we will base it on the global setting
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		foreach ($select as $val)
+		{
+			$val = trim($val);
+
+			if ($val !== '')
+			{
+				$this->qb_select[] = $val;
+				$this->qb_no_escape[] = $escape;
+
+				if ($this->qb_caching === TRUE)
+				{
+					$this->qb_cache_select[] = $val;
+					$this->qb_cache_exists[] = 'select';
+					$this->qb_cache_no_escape[] = $escape;
+				}
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Max
+	 *
+	 * Generates a SELECT MAX(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	CI_DB_query_builder
+	 */
+	public function select_max($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'MAX');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Min
+	 *
+	 * Generates a SELECT MIN(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	CI_DB_query_builder
+	 */
+	public function select_min($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'MIN');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Average
+	 *
+	 * Generates a SELECT AVG(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	CI_DB_query_builder
+	 */
+	public function select_avg($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'AVG');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Sum
+	 *
+	 * Generates a SELECT SUM(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	CI_DB_query_builder
+	 */
+	public function select_sum($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'SUM');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * SELECT [MAX|MIN|AVG|SUM]()
+	 *
+	 * @used-by	select_max()
+	 * @used-by	select_min()
+	 * @used-by	select_avg()
+	 * @used-by	select_sum()
+	 *
+	 * @param	string	$select	Field name
+	 * @param	string	$alias
+	 * @param	string	$type
+	 * @return	CI_DB_query_builder
+	 */
+	protected function _max_min_avg_sum($select = '', $alias = '', $type = 'MAX')
+	{
+		if ( ! is_string($select) OR $select === '')
+		{
+			$this->display_error('db_invalid_query');
+		}
+
+		$type = strtoupper($type);
+
+		if ( ! in_array($type, array('MAX', 'MIN', 'AVG', 'SUM')))
+		{
+			show_error('Invalid function type: '.$type);
+		}
+
+		if ($alias === '')
+		{
+			$alias = $this->_create_alias_from_table(trim($select));
+		}
+
+		$sql = $type.'('.$this->protect_identifiers(trim($select)).') AS '.$this->escape_identifiers(trim($alias));
+
+		$this->qb_select[] = $sql;
+		$this->qb_no_escape[] = NULL;
+
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_select[] = $sql;
+			$this->qb_cache_exists[] = 'select';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Determines the alias name based on the table
+	 *
+	 * @param	string	$item
+	 * @return	string
+	 */
+	protected function _create_alias_from_table($item)
+	{
+		if (strpos($item, '.') !== FALSE)
+		{
+			$item = explode('.', $item);
+			return end($item);
+		}
+
+		return $item;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * DISTINCT
+	 *
+	 * Sets a flag which tells the query string compiler to add DISTINCT
+	 *
+	 * @param	bool	$val
+	 * @return	CI_DB_query_builder
+	 */
+	public function distinct($val = TRUE)
+	{
+		$this->qb_distinct = is_bool($val) ? $val : TRUE;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * From
+	 *
+	 * Generates the FROM portion of the query
+	 *
+	 * @param	mixed	$from	can be a string or array
+	 * @return	CI_DB_query_builder
+	 */
+	public function from($from)
+	{
+		foreach ((array) $from as $val)
+		{
+			if (strpos($val, ',') !== FALSE)
+			{
+				foreach (explode(',', $val) as $v)
+				{
+					$v = trim($v);
+					$this->_track_aliases($v);
+
+					$this->qb_from[] = $v = $this->protect_identifiers($v, TRUE, NULL, FALSE);
+
+					if ($this->qb_caching === TRUE)
+					{
+						$this->qb_cache_from[] = $v;
+						$this->qb_cache_exists[] = 'from';
+					}
+				}
+			}
+			else
+			{
+				$val = trim($val);
+
+				// Extract any aliases that might exist. We use this information
+				// in the protect_identifiers to know whether to add a table prefix
+				$this->_track_aliases($val);
+
+				$this->qb_from[] = $val = $this->protect_identifiers($val, TRUE, NULL, FALSE);
+
+				if ($this->qb_caching === TRUE)
+				{
+					$this->qb_cache_from[] = $val;
+					$this->qb_cache_exists[] = 'from';
+				}
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * JOIN
+	 *
+	 * Generates the JOIN portion of the query
+	 *
+	 * @param	string
+	 * @param	string	the join condition
+	 * @param	string	the type of join
+	 * @param	string	whether not to try to escape identifiers
+	 * @return	CI_DB_query_builder
+	 */
+	public function join($table, $cond, $type = '', $escape = NULL)
+	{
+		if ($type !== '')
+		{
+			$type = strtoupper(trim($type));
+
+			if ( ! in_array($type, array('LEFT', 'RIGHT', 'OUTER', 'INNER', 'LEFT OUTER', 'RIGHT OUTER'), TRUE))
+			{
+				$type = '';
+			}
+			else
+			{
+				$type .= ' ';
+			}
+		}
+
+		// Extract any aliases that might exist. We use this information
+		// in the protect_identifiers to know whether to add a table prefix
+		$this->_track_aliases($table);
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		if ( ! $this->_has_operator($cond))
+		{
+			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
+		}
+		elseif ($escape === FALSE)
+		{
+			$cond = ' ON '.$cond;
+		}
+		else
+		{
+			// Split multiple conditions
+			if (preg_match_all('/\sAND\s|\sOR\s/i', $cond, $joints, PREG_OFFSET_CAPTURE))
+			{
+				$conditions = array();
+				$joints = $joints[0];
+				array_unshift($joints, array('', 0));
+
+				for ($i = count($joints) - 1, $pos = strlen($cond); $i >= 0; $i--)
+				{
+					$joints[$i][1] += strlen($joints[$i][0]); // offset
+					$conditions[$i] = substr($cond, $joints[$i][1], $pos - $joints[$i][1]);
+					$pos = $joints[$i][1] - strlen($joints[$i][0]);
+					$joints[$i] = $joints[$i][0];
+				}
+			}
+			else
+			{
+				$conditions = array($cond);
+				$joints = array('');
+			}
+
+			$cond = ' ON ';
+			for ($i = 0, $c = count($conditions); $i < $c; $i++)
+			{
+				$operator = $this->_get_operator($conditions[$i]);
+				$cond .= $joints[$i];
+				$cond .= preg_match("/(\(*)?([\[\]\w\.'-]+)".preg_quote($operator)."(.*)/i", $conditions[$i], $match)
+					? $match[1].$this->protect_identifiers($match[2]).$operator.$this->protect_identifiers($match[3])
+					: $conditions[$i];
+			}
+		}
+
+		// Do we want to escape the table name?
+		if ($escape === TRUE)
+		{
+			$table = $this->protect_identifiers($table, TRUE, NULL, FALSE);
+		}
+
+		// Assemble the JOIN statement
+		$this->qb_join[] = $join = $type.'JOIN '.$table.$cond;
+
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_join[] = $join;
+			$this->qb_cache_exists[] = 'join';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * WHERE
+	 *
+	 * Generates the WHERE portion of the query.
+	 * Separates multiple calls with 'AND'.
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @param	bool
+	 * @return	CI_DB_query_builder
+	 */
+	public function where($key, $value = NULL, $escape = NULL)
+	{
+		return $this->_wh('qb_where', $key, $value, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR WHERE
+	 *
+	 * Generates the WHERE portion of the query.
+	 * Separates multiple calls with 'OR'.
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @param	bool
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_where($key, $value = NULL, $escape = NULL)
+	{
+		return $this->_wh('qb_where', $key, $value, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * WHERE, HAVING
+	 *
+	 * @used-by	where()
+	 * @used-by	or_where()
+	 * @used-by	having()
+	 * @used-by	or_having()
+	 *
+	 * @param	string	$qb_key	'qb_where' or 'qb_having'
+	 * @param	mixed	$key
+	 * @param	mixed	$value
+	 * @param	string	$type
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	protected function _wh($qb_key, $key, $value = NULL, $type = 'AND ', $escape = NULL)
+	{
+		$qb_cache_key = ($qb_key === 'qb_having') ? 'qb_cache_having' : 'qb_cache_where';
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		// If the escape value was not set will base it on the global setting
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		foreach ($key as $k => $v)
+		{
+			$prefix = (count($this->$qb_key) === 0 && count($this->$qb_cache_key) === 0)
+				? $this->_group_get_type('')
+				: $this->_group_get_type($type);
+
+			if ($v !== NULL)
+			{
+				if ($escape === TRUE)
+				{
+					$v = ' '.$this->escape($v);
+				}
+
+				if ( ! $this->_has_operator($k))
+				{
+					$k .= ' = ';
+				}
+			}
+			elseif ( ! $this->_has_operator($k))
+			{
+				// value appears not to have been set, assign the test to IS NULL
+				$k .= ' IS NULL';
+			}
+			elseif (preg_match('/\s*(!?=|<>|\sIS(?:\s+NOT)?\s)\s*$/i', $k, $match, PREG_OFFSET_CAPTURE))
+			{
+				$k = substr($k, 0, $match[0][1]).($match[1][0] === '=' ? ' IS NULL' : ' IS NOT NULL');
+			}
+
+			$this->{$qb_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
+			if ($this->qb_caching === TRUE)
+			{
+				$this->{$qb_cache_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
+				$this->qb_cache_exists[] = substr($qb_key, 3);
+			}
+
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * WHERE IN
+	 *
+	 * Generates a WHERE field IN('item', 'item') SQL query,
+	 * joined with 'AND' if appropriate.
+	 *
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function where_in($key = NULL, $values = NULL, $escape = NULL)
+	{
+		return $this->_where_in($key, $values, FALSE, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR WHERE IN
+	 *
+	 * Generates a WHERE field IN('item', 'item') SQL query,
+	 * joined with 'OR' if appropriate.
+	 *
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_where_in($key = NULL, $values = NULL, $escape = NULL)
+	{
+		return $this->_where_in($key, $values, FALSE, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * WHERE NOT IN
+	 *
+	 * Generates a WHERE field NOT IN('item', 'item') SQL query,
+	 * joined with 'AND' if appropriate.
+	 *
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function where_not_in($key = NULL, $values = NULL, $escape = NULL)
+	{
+		return $this->_where_in($key, $values, TRUE, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR WHERE NOT IN
+	 *
+	 * Generates a WHERE field NOT IN('item', 'item') SQL query,
+	 * joined with 'OR' if appropriate.
+	 *
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_where_not_in($key = NULL, $values = NULL, $escape = NULL)
+	{
+		return $this->_where_in($key, $values, TRUE, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Internal WHERE IN
+	 *
+	 * @used-by	where_in()
+	 * @used-by	or_where_in()
+	 * @used-by	where_not_in()
+	 * @used-by	or_where_not_in()
+	 *
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$not	If the statement would be IN or NOT IN
+	 * @param	string	$type
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	protected function _where_in($key = NULL, $values = NULL, $not = FALSE, $type = 'AND ', $escape = NULL)
+	{
+		if ($key === NULL OR $values === NULL)
+		{
+			return $this;
+		}
+
+		if ( ! is_array($values))
+		{
+			$values = array($values);
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		$not = ($not) ? ' NOT' : '';
+
+		if ($escape === TRUE)
+		{
+			$where_in = array();
+			foreach ($values as $value)
+			{
+				$where_in[] = $this->escape($value);
+			}
+		}
+		else
+		{
+			$where_in = array_values($values);
+		}
+
+		$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0)
+			? $this->_group_get_type('')
+			: $this->_group_get_type($type);
+
+		$where_in = array(
+			'condition' => $prefix.$key.$not.' IN('.implode(', ', $where_in).')',
+			'escape' => $escape
+		);
+
+		$this->qb_where[] = $where_in;
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_where[] = $where_in;
+			$this->qb_cache_exists[] = 'where';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * LIKE
+	 *
+	 * Generates a %LIKE% portion of the query.
+	 * Separates multiple calls with 'AND'.
+	 *
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function like($field, $match = '', $side = 'both', $escape = NULL)
+	{
+		return $this->_like($field, $match, 'AND ', $side, '', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * NOT LIKE
+	 *
+	 * Generates a NOT LIKE portion of the query.
+	 * Separates multiple calls with 'AND'.
+	 *
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function not_like($field, $match = '', $side = 'both', $escape = NULL)
+	{
+		return $this->_like($field, $match, 'AND ', $side, 'NOT', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR LIKE
+	 *
+	 * Generates a %LIKE% portion of the query.
+	 * Separates multiple calls with 'OR'.
+	 *
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_like($field, $match = '', $side = 'both', $escape = NULL)
+	{
+		return $this->_like($field, $match, 'OR ', $side, '', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR NOT LIKE
+	 *
+	 * Generates a NOT LIKE portion of the query.
+	 * Separates multiple calls with 'OR'.
+	 *
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_not_like($field, $match = '', $side = 'both', $escape = NULL)
+	{
+		return $this->_like($field, $match, 'OR ', $side, 'NOT', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Internal LIKE
+	 *
+	 * @used-by	like()
+	 * @used-by	or_like()
+	 * @used-by	not_like()
+	 * @used-by	or_not_like()
+	 *
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$type
+	 * @param	string	$side
+	 * @param	string	$not
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	protected function _like($field, $match = '', $type = 'AND ', $side = 'both', $not = '', $escape = NULL)
+	{
+		if ( ! is_array($field))
+		{
+			$field = array($field => $match);
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+		// lowercase $side in case somebody writes e.g. 'BEFORE' instead of 'before' (doh)
+		$side = strtolower($side);
+
+		foreach ($field as $k => $v)
+		{
+			$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0)
+				? $this->_group_get_type('') : $this->_group_get_type($type);
+
+			if ($escape === TRUE)
+			{
+				$v = $this->escape_like_str($v);
+			}
+
+			if ($side === 'none')
+			{
+				$like_statement = "{$prefix} {$k} {$not} LIKE '{$v}'";
+			}
+			elseif ($side === 'before')
+			{
+				$like_statement = "{$prefix} {$k} {$not} LIKE '%{$v}'";
+			}
+			elseif ($side === 'after')
+			{
+				$like_statement = "{$prefix} {$k} {$not} LIKE '{$v}%'";
+			}
+			else
+			{
+				$like_statement = "{$prefix} {$k} {$not} LIKE '%{$v}%'";
+			}
+
+			// some platforms require an escape sequence definition for LIKE wildcards
+			if ($escape === TRUE && $this->_like_escape_str !== '')
+			{
+				$like_statement .= sprintf($this->_like_escape_str, $this->_like_escape_chr);
+			}
+
+			$this->qb_where[] = array('condition' => $like_statement, 'escape' => $escape);
+			if ($this->qb_caching === TRUE)
+			{
+				$this->qb_cache_where[] = array('condition' => $like_statement, 'escape' => $escape);
+				$this->qb_cache_exists[] = 'where';
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group.
+	 *
+	 * @param	string	$not	(Internal use only)
+	 * @param	string	$type	(Internal use only)
+	 * @return	CI_DB_query_builder
+	 */
+	public function group_start($not = '', $type = 'AND ')
+	{
+		$type = $this->_group_get_type($type);
+
+		$this->qb_where_group_started = TRUE;
+		$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0) ? '' : $type;
+		$where = array(
+			'condition' => $prefix.$not.str_repeat(' ', ++$this->qb_where_group_count).' (',
+			'escape' => FALSE
+		);
+
+		$this->qb_where[] = $where;
+		if ($this->qb_caching)
+		{
+			$this->qb_cache_where[] = $where;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but ORs the group
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_group_start()
+	{
+		return $this->group_start('', 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but NOTs the group
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function not_group_start()
+	{
+		return $this->group_start('NOT ', 'AND ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but OR NOTs the group
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_not_group_start()
+	{
+		return $this->group_start('NOT ', 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Ends a query group
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function group_end()
+	{
+		$this->qb_where_group_started = FALSE;
+		$where = array(
+			'condition' => str_repeat(' ', $this->qb_where_group_count--).')',
+			'escape' => FALSE
+		);
+
+		$this->qb_where[] = $where;
+		if ($this->qb_caching)
+		{
+			$this->qb_cache_where[] = $where;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Group_get_type
+	 *
+	 * @used-by	group_start()
+	 * @used-by	_like()
+	 * @used-by	_wh()
+	 * @used-by	_where_in()
+	 *
+	 * @param	string	$type
+	 * @return	string
+	 */
+	protected function _group_get_type($type)
+	{
+		if ($this->qb_where_group_started)
+		{
+			$type = '';
+			$this->qb_where_group_started = FALSE;
+		}
+
+		return $type;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * GROUP BY
+	 *
+	 * @param	string	$by
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function group_by($by, $escape = NULL)
+	{
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		if (is_string($by))
+		{
+			$by = ($escape === TRUE)
+				? explode(',', $by)
+				: array($by);
+		}
+
+		foreach ($by as $val)
+		{
+			$val = trim($val);
+
+			if ($val !== '')
+			{
+				$val = array('field' => $val, 'escape' => $escape);
+
+				$this->qb_groupby[] = $val;
+				if ($this->qb_caching === TRUE)
+				{
+					$this->qb_cache_groupby[] = $val;
+					$this->qb_cache_exists[] = 'groupby';
+				}
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * HAVING
+	 *
+	 * Separates multiple calls with 'AND'.
+	 *
+	 * @param	string	$key
+	 * @param	string	$value
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function having($key, $value = NULL, $escape = NULL)
+	{
+		return $this->_wh('qb_having', $key, $value, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR HAVING
+	 *
+	 * Separates multiple calls with 'OR'.
+	 *
+	 * @param	string	$key
+	 * @param	string	$value
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function or_having($key, $value = NULL, $escape = NULL)
+	{
+		return $this->_wh('qb_having', $key, $value, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY
+	 *
+	 * @param	string	$orderby
+	 * @param	string	$direction	ASC, DESC or RANDOM
+	 * @param	bool	$escape
+	 * @return	CI_DB_query_builder
+	 */
+	public function order_by($orderby, $direction = '', $escape = NULL)
+	{
+		$direction = strtoupper(trim($direction));
+
+		if ($direction === 'RANDOM')
+		{
+			$direction = '';
+
+			// Do we have a seed value?
+			$orderby = ctype_digit((string) $orderby)
+				? sprintf($this->_random_keyword[1], $orderby)
+				: $this->_random_keyword[0];
+		}
+		elseif (empty($orderby))
+		{
+			return $this;
+		}
+		elseif ($direction !== '')
+		{
+			$direction = in_array($direction, array('ASC', 'DESC'), TRUE) ? ' '.$direction : '';
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		if ($escape === FALSE)
+		{
+			$qb_orderby[] = array('field' => $orderby, 'direction' => $direction, 'escape' => FALSE);
+		}
+		else
+		{
+			$qb_orderby = array();
+			foreach (explode(',', $orderby) as $field)
+			{
+				$qb_orderby[] = ($direction === '' && preg_match('/\s+(ASC|DESC)$/i', rtrim($field), $match, PREG_OFFSET_CAPTURE))
+					? array('field' => ltrim(substr($field, 0, $match[0][1])), 'direction' => ' '.$match[1][0], 'escape' => TRUE)
+					: array('field' => trim($field), 'direction' => $direction, 'escape' => TRUE);
+			}
+		}
+
+		$this->qb_orderby = array_merge($this->qb_orderby, $qb_orderby);
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_orderby = array_merge($this->qb_cache_orderby, $qb_orderby);
+			$this->qb_cache_exists[] = 'orderby';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * LIMIT
+	 *
+	 * @param	int	$value	LIMIT value
+	 * @param	int	$offset	OFFSET value
+	 * @return	CI_DB_query_builder
+	 */
+	public function limit($value, $offset = 0)
+	{
+		is_null($value) OR $this->qb_limit = (int) $value;
+		empty($offset) OR $this->qb_offset = (int) $offset;
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the OFFSET value
+	 *
+	 * @param	int	$offset	OFFSET value
+	 * @return	CI_DB_query_builder
+	 */
+	public function offset($offset)
+	{
+		empty($offset) OR $this->qb_offset = (int) $offset;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * LIMIT string
+	 *
+	 * Generates a platform-specific LIMIT clause.
+	 *
+	 * @param	string	$sql	SQL Query
+	 * @return	string
+	 */
+	protected function _limit($sql)
+	{
+		return $sql.' LIMIT '.($this->qb_offset ? $this->qb_offset.', ' : '').(int) $this->qb_limit;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set" function.
+	 *
+	 * Allows key/value pairs to be set for inserting or updating
+	 *
+	 * @param	mixed
+	 * @param	string
+	 * @param	bool
+	 * @return	CI_DB_query_builder
+	 */
+	public function set($key, $value = '', $escape = NULL)
+	{
+		$key = $this->_object_to_array($key);
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		foreach ($key as $k => $v)
+		{
+			$this->qb_set[$this->protect_identifiers($k, FALSE, $escape)] = ($escape)
+				? $this->escape($v) : $v;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get SELECT query string
+	 *
+	 * Compiles a SELECT query string and returns the sql.
+	 *
+	 * @param	string	the table name to select from (optional)
+	 * @param	bool	TRUE: resets QB values; FALSE: leave QB values alone
+	 * @return	string
+	 */
+	public function get_compiled_select($table = '', $reset = TRUE)
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		$select = $this->_compile_select();
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_select();
+		}
+
+		return $select;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get
+	 *
+	 * Compiles the select statement based on the other functions called
+	 * and runs the query
+	 *
+	 * @param	string	the table
+	 * @param	string	the limit clause
+	 * @param	string	the offset clause
+	 * @return	CI_DB_result
+	 */
+	public function get($table = '', $limit = NULL, $offset = NULL)
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		if ( ! empty($limit))
+		{
+			$this->limit($limit, $offset);
+		}
+
+		$result = $this->query($this->_compile_select());
+		$this->_reset_select();
+		return $result;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * "Count All Results" query
+	 *
+	 * Generates a platform-specific query string that counts all records
+	 * returned by an Query Builder query.
+	 *
+	 * @param	string
+	 * @param	bool	the reset clause
+	 * @return	int
+	 */
+	public function count_all_results($table = '', $reset = TRUE)
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		// ORDER BY usage is often problematic here (most notably
+		// on Microsoft SQL Server) and ultimately unnecessary
+		// for selecting COUNT(*) ...
+		if ( ! empty($this->qb_orderby))
+		{
+			$orderby = $this->qb_orderby;
+			$this->qb_orderby = NULL;
+		}
+
+		$result = ($this->qb_distinct === TRUE OR ! empty($this->qb_groupby) OR ! empty($this->qb_cache_groupby) OR $this->qb_limit OR $this->qb_offset)
+			? $this->query($this->_count_string.$this->protect_identifiers('numrows')."\nFROM (\n".$this->_compile_select()."\n) CI_count_all_results")
+			: $this->query($this->_compile_select($this->_count_string.$this->protect_identifiers('numrows')));
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_select();
+		}
+		// If we've previously reset the qb_orderby values, get them back
+		elseif ( ! isset($this->qb_orderby))
+		{
+			$this->qb_orderby = $orderby;
+		}
+
+		if ($result->num_rows() === 0)
+		{
+			return 0;
+		}
+
+		$row = $result->row();
+		return (int) $row->numrows;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get_Where
+	 *
+	 * Allows the where clause, limit and offset to be added directly
+	 *
+	 * @param	string	$table
+	 * @param	string	$where
+	 * @param	int	$limit
+	 * @param	int	$offset
+	 * @return	CI_DB_result
+	 */
+	public function get_where($table = '', $where = NULL, $limit = NULL, $offset = NULL)
+	{
+		if ($table !== '')
+		{
+			$this->from($table);
+		}
+
+		if ($where !== NULL)
+		{
+			$this->where($where);
+		}
+
+		if ( ! empty($limit))
+		{
+			$this->limit($limit, $offset);
+		}
+
+		$result = $this->query($this->_compile_select());
+		$this->_reset_select();
+		return $result;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert_Batch
+	 *
+	 * Compiles batch insert strings and runs the queries
+	 *
+	 * @param	string	$table	Table to insert into
+	 * @param	array	$set 	An associative array of insert values
+	 * @param	bool	$escape	Whether to escape values and identifiers
+	 * @return	int	Number of rows inserted or FALSE on failure
+	 */
+	public function insert_batch($table, $set = NULL, $escape = NULL, $batch_size = 100)
+	{
+		if ($set === NULL)
+		{
+			if (empty($this->qb_set))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+			}
+		}
+		else
+		{
+			if (empty($set))
+			{
+				return ($this->db_debug) ? $this->display_error('insert_batch() called with no data') : FALSE;
+			}
+
+			$this->set_insert_batch($set, '', $escape);
+		}
+
+		if (strlen($table) === 0)
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+
+		// Batch this baby
+		$affected_rows = 0;
+		for ($i = 0, $total = count($this->qb_set); $i < $total; $i += $batch_size)
+		{
+			if ($this->query($this->_insert_batch($this->protect_identifiers($table, TRUE, $escape, FALSE), $this->qb_keys, array_slice($this->qb_set, $i, $batch_size))))
+			{
+				$affected_rows += $this->affected_rows();
+			}
+		}
+
+		$this->_reset_write();
+		return $affected_rows;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set_insert_batch" function.  Allows key/value pairs to be set for batch inserts
+	 *
+	 * @param	mixed
+	 * @param	string
+	 * @param	bool
+	 * @return	CI_DB_query_builder
+	 */
+	public function set_insert_batch($key, $value = '', $escape = NULL)
+	{
+		$key = $this->_object_to_array_batch($key);
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		$keys = array_keys($this->_object_to_array(reset($key)));
+		sort($keys);
+
+		foreach ($key as $row)
+		{
+			$row = $this->_object_to_array($row);
+			if (count(array_diff($keys, array_keys($row))) > 0 OR count(array_diff(array_keys($row), $keys)) > 0)
+			{
+				// batch function above returns an error on an empty array
+				$this->qb_set[] = array();
+				return;
+			}
+
+			ksort($row); // puts $row in the same order as our keys
+
+			if ($escape !== FALSE)
+			{
+				$clean = array();
+				foreach ($row as $value)
+				{
+					$clean[] = $this->escape($value);
+				}
+
+				$row = $clean;
+			}
+
+			$this->qb_set[] = '('.implode(',', $row).')';
+		}
+
+		foreach ($keys as $k)
+		{
+			$this->qb_keys[] = $this->protect_identifiers($k, FALSE, $escape);
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get INSERT query string
+	 *
+	 * Compiles an insert query and returns the sql
+	 *
+	 * @param	string	the table to insert into
+	 * @param	bool	TRUE: reset QB values; FALSE: leave QB values alone
+	 * @return	string
+	 */
+	public function get_compiled_insert($table = '', $reset = TRUE)
+	{
+		if ($this->_validate_insert($table) === FALSE)
+		{
+			return FALSE;
+		}
+
+		$sql = $this->_insert(
+			$this->protect_identifiers(
+				$this->qb_from[0], TRUE, NULL, FALSE
+			),
+			array_keys($this->qb_set),
+			array_values($this->qb_set)
+		);
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_write();
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert
+	 *
+	 * Compiles an insert string and runs the query
+	 *
+	 * @param	string	the table to insert data into
+	 * @param	array	an associative array of insert values
+	 * @param	bool	$escape	Whether to escape values and identifiers
+	 * @return	bool	TRUE on success, FALSE on failure
+	 */
+	public function insert($table = '', $set = NULL, $escape = NULL)
+	{
+		if ($set !== NULL)
+		{
+			$this->set($set, '', $escape);
+		}
+
+		if ($this->_validate_insert($table) === FALSE)
+		{
+			return FALSE;
+		}
+
+		$sql = $this->_insert(
+			$this->protect_identifiers(
+				$this->qb_from[0], TRUE, $escape, FALSE
+			),
+			array_keys($this->qb_set),
+			array_values($this->qb_set)
+		);
+
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate Insert
+	 *
+	 * This method is used by both insert() and get_compiled_insert() to
+	 * validate that the there data is actually being set and that table
+	 * has been chosen to be inserted into.
+	 *
+	 * @param	string	the table to insert data into
+	 * @return	string
+	 */
+	protected function _validate_insert($table = '')
+	{
+		if (count($this->qb_set) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+		}
+
+		if ($table !== '')
+		{
+			$this->qb_from[0] = $table;
+		}
+		elseif ( ! isset($this->qb_from[0]))
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+		}
+
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Replace
+	 *
+	 * Compiles an replace into string and runs the query
+	 *
+	 * @param	string	the table to replace data into
+	 * @param	array	an associative array of insert values
+	 * @return	bool	TRUE on success, FALSE on failure
+	 */
+	public function replace($table = '', $set = NULL)
+	{
+		if ($set !== NULL)
+		{
+			$this->set($set);
+		}
+
+		if (count($this->qb_set) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+		}
+
+		if ($table === '')
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+
+		$sql = $this->_replace($this->protect_identifiers($table, TRUE, NULL, FALSE), array_keys($this->qb_set), array_values($this->qb_set));
+
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Replace statement
+	 *
+	 * Generates a platform-specific replace string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @param	array	the insert keys
+	 * @param	array	the insert values
+	 * @return	string
+	 */
+	protected function _replace($table, $keys, $values)
+	{
+		return 'REPLACE INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * Note: This is only used (and overridden) by MySQL and CUBRID.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get UPDATE query string
+	 *
+	 * Compiles an update query and returns the sql
+	 *
+	 * @param	string	the table to update
+	 * @param	bool	TRUE: reset QB values; FALSE: leave QB values alone
+	 * @return	string
+	 */
+	public function get_compiled_update($table = '', $reset = TRUE)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if ($this->_validate_update($table) === FALSE)
+		{
+			return FALSE;
+		}
+
+		$sql = $this->_update($this->qb_from[0], $this->qb_set);
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_write();
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * UPDATE
+	 *
+	 * Compiles an update string and runs the query.
+	 *
+	 * @param	string	$table
+	 * @param	array	$set	An associative array of update values
+	 * @param	mixed	$where
+	 * @param	int	$limit
+	 * @return	bool	TRUE on success, FALSE on failure
+	 */
+	public function update($table = '', $set = NULL, $where = NULL, $limit = NULL)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if ($set !== NULL)
+		{
+			$this->set($set);
+		}
+
+		if ($this->_validate_update($table) === FALSE)
+		{
+			return FALSE;
+		}
+
+		if ($where !== NULL)
+		{
+			$this->where($where);
+		}
+
+		if ( ! empty($limit))
+		{
+			$this->limit($limit);
+		}
+
+		$sql = $this->_update($this->qb_from[0], $this->qb_set);
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate Update
+	 *
+	 * This method is used by both update() and get_compiled_update() to
+	 * validate that data is actually being set and that a table has been
+	 * chosen to be update.
+	 *
+	 * @param	string	the table to update data on
+	 * @return	bool
+	 */
+	protected function _validate_update($table)
+	{
+		if (count($this->qb_set) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+		}
+
+		if ($table !== '')
+		{
+			$this->qb_from = array($this->protect_identifiers($table, TRUE, NULL, FALSE));
+		}
+		elseif ( ! isset($this->qb_from[0]))
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+		}
+
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update_Batch
+	 *
+	 * Compiles an update string and runs the query
+	 *
+	 * @param	string	the table to retrieve the results from
+	 * @param	array	an associative array of update values
+	 * @param	string	the where key
+	 * @return	int	number of rows affected or FALSE on failure
+	 */
+	public function update_batch($table, $set = NULL, $index = NULL, $batch_size = 100)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if ($index === NULL)
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_index') : FALSE;
+		}
+
+		if ($set === NULL)
+		{
+			if (empty($this->qb_set_ub))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+			}
+		}
+		else
+		{
+			if (empty($set))
+			{
+				return ($this->db_debug) ? $this->display_error('update_batch() called with no data') : FALSE;
+			}
+
+			$this->set_update_batch($set, $index);
+		}
+
+		if (strlen($table) === 0)
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+
+		// Batch this baby
+		$affected_rows = 0;
+		for ($i = 0, $total = count($this->qb_set_ub); $i < $total; $i += $batch_size)
+		{
+			if ($this->query($this->_update_batch($this->protect_identifiers($table, TRUE, NULL, FALSE), array_slice($this->qb_set_ub, $i, $batch_size), $index)))
+			{
+				$affected_rows += $this->affected_rows();
+			}
+
+			$this->qb_where = array();
+		}
+
+		$this->_reset_write();
+		return $affected_rows;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update_Batch statement
+	 *
+	 * Generates a platform-specific batch update string from the supplied data
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
+	 * @return	string
+	 */
+	protected function _update_batch($table, $values, $index)
+	{
+		$ids = array();
+		foreach ($values as $key => $val)
+		{
+			$ids[] = $val[$index]['value'];
+
+			foreach (array_keys($val) as $field)
+			{
+				if ($field !== $index)
+				{
+					$final[$val[$field]['field']][] = 'WHEN '.$val[$index]['field'].' = '.$val[$index]['value'].' THEN '.$val[$field]['value'];
+				}
+			}
+		}
+
+		$cases = '';
+		foreach ($final as $k => $v)
+		{
+			$cases .= $k." = CASE \n"
+				.implode("\n", $v)."\n"
+				.'ELSE '.$k.' END, ';
+		}
+
+		$this->where($val[$index]['field'].' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set_update_batch" function.  Allows key/value pairs to be set for batch updating
+	 *
+	 * @param	array
+	 * @param	string
+	 * @param	bool
+	 * @return	CI_DB_query_builder
+	 */
+	public function set_update_batch($key, $index = '', $escape = NULL)
+	{
+		$key = $this->_object_to_array_batch($key);
+
+		if ( ! is_array($key))
+		{
+			// @todo error
+		}
+
+		is_bool($escape) OR $escape = $this->_protect_identifiers;
+
+		foreach ($key as $k => $v)
+		{
+			$index_set = FALSE;
+			$clean = array();
+			foreach ($v as $k2 => $v2)
+			{
+				if ($k2 === $index)
+				{
+					$index_set = TRUE;
+				}
+
+				$clean[$k2] = array(
+					'field'  => $this->protect_identifiers($k2, FALSE, $escape),
+					'value'  => ($escape === FALSE ? $v2 : $this->escape($v2))
+				);
+			}
+
+			if ($index_set === FALSE)
+			{
+				return $this->display_error('db_batch_missing_index');
+			}
+
+			$this->qb_set_ub[] = $clean;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Empty Table
+	 *
+	 * Compiles a delete string and runs "DELETE FROM table"
+	 *
+	 * @param	string	the table to empty
+	 * @return	bool	TRUE on success, FALSE on failure
+	 */
+	public function empty_table($table = '')
+	{
+		if ($table === '')
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+		else
+		{
+			$table = $this->protect_identifiers($table, TRUE, NULL, FALSE);
+		}
+
+		$sql = $this->_delete($table);
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Truncate
+	 *
+	 * Compiles a truncate string and runs the query
+	 * If the database does not support the truncate() command
+	 * This function maps to "DELETE FROM table"
+	 *
+	 * @param	string	the table to truncate
+	 * @return	bool	TRUE on success, FALSE on failure
+	 */
+	public function truncate($table = '')
+	{
+		if ($table === '')
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+		else
+		{
+			$table = $this->protect_identifiers($table, TRUE, NULL, FALSE);
+		}
+
+		$sql = $this->_truncate($table);
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Truncate statement
+	 *
+	 * Generates a platform-specific truncate string from the supplied data
+	 *
+	 * If the database does not support the truncate() command,
+	 * then this method maps to 'DELETE FROM table'
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	protected function _truncate($table)
+	{
+		return 'TRUNCATE '.$table;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get DELETE query string
+	 *
+	 * Compiles a delete query string and returns the sql
+	 *
+	 * @param	string	the table to delete from
+	 * @param	bool	TRUE: reset QB values; FALSE: leave QB values alone
+	 * @return	string
+	 */
+	public function get_compiled_delete($table = '', $reset = TRUE)
+	{
+		$this->return_delete_sql = TRUE;
+		$sql = $this->delete($table, '', NULL, $reset);
+		$this->return_delete_sql = FALSE;
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Delete
+	 *
+	 * Compiles a delete string and runs the query
+	 *
+	 * @param	mixed	the table(s) to delete from. String or array
+	 * @param	mixed	the where clause
+	 * @param	mixed	the limit clause
+	 * @param	bool
+	 * @return	mixed
+	 */
+	public function delete($table = '', $where = '', $limit = NULL, $reset_data = TRUE)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if ($table === '')
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+		elseif (is_array($table))
+		{
+			empty($where) && $reset_data = FALSE;
+
+			foreach ($table as $single_table)
+			{
+				$this->delete($single_table, $where, $limit, $reset_data);
+			}
+
+			return;
+		}
+		else
+		{
+			$table = $this->protect_identifiers($table, TRUE, NULL, FALSE);
+		}
+
+		if ($where !== '')
+		{
+			$this->where($where);
+		}
+
+		if ( ! empty($limit))
+		{
+			$this->limit($limit);
+		}
+
+		if (count($this->qb_where) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_del_must_use_where') : FALSE;
+		}
+
+		$sql = $this->_delete($table);
+		if ($reset_data)
+		{
+			$this->_reset_write();
+		}
+
+		return ($this->return_delete_sql === TRUE) ? $sql : $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Delete statement
+	 *
+	 * Generates a platform-specific delete string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	protected function _delete($table)
+	{
+		return 'DELETE FROM '.$table.$this->_compile_wh('qb_where')
+			.($this->qb_limit ? ' LIMIT '.$this->qb_limit : '');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * DB Prefix
+	 *
+	 * Prepends a database prefix if one exists in configuration
+	 *
+	 * @param	string	the table
+	 * @return	string
+	 */
+	public function dbprefix($table = '')
+	{
+		if ($table === '')
+		{
+			$this->display_error('db_table_name_required');
+		}
+
+		return $this->dbprefix.$table;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Set DB Prefix
+	 *
+	 * Set's the DB Prefix to something new without needing to reconnect
+	 *
+	 * @param	string	the prefix
+	 * @return	string
+	 */
+	public function set_dbprefix($prefix = '')
+	{
+		return $this->dbprefix = $prefix;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Track Aliases
+	 *
+	 * Used to track SQL statements written with aliased tables.
+	 *
+	 * @param	string	The table to inspect
+	 * @return	string
+	 */
+	protected function _track_aliases($table)
+	{
+		if (is_array($table))
+		{
+			foreach ($table as $t)
+			{
+				$this->_track_aliases($t);
+			}
+			return;
+		}
+
+		// Does the string contain a comma?  If so, we need to separate
+		// the string into discreet statements
+		if (strpos($table, ',') !== FALSE)
+		{
+			return $this->_track_aliases(explode(',', $table));
+		}
+
+		// if a table alias is used we can recognize it by a space
+		if (strpos($table, ' ') !== FALSE)
+		{
+			// if the alias is written with the AS keyword, remove it
+			$table = preg_replace('/\s+AS\s+/i', ' ', $table);
+
+			// Grab the alias
+			$table = trim(strrchr($table, ' '));
+
+			// Store the alias, if it doesn't already exist
+			if ( ! in_array($table, $this->qb_aliased_tables, TRUE))
+			{
+				$this->qb_aliased_tables[] = $table;
+				if ($this->qb_caching === TRUE && ! in_array($table, $this->qb_cache_aliased_tables, TRUE))
+				{
+					$this->qb_cache_aliased_tables[] = $table;
+					$this->qb_cache_exists[] = 'aliased_tables';
+				}
+			}
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Compile the SELECT statement
+	 *
+	 * Generates a query string based on which functions were used.
+	 * Should not be called directly.
+	 *
+	 * @param	bool	$select_override
+	 * @return	string
+	 */
+	protected function _compile_select($select_override = FALSE)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		// Write the "select" portion of the query
+		if ($select_override !== FALSE)
+		{
+			$sql = $select_override;
+		}
+		else
+		{
+			$sql = ( ! $this->qb_distinct) ? 'SELECT ' : 'SELECT DISTINCT ';
+
+			if (count($this->qb_select) === 0)
+			{
+				$sql .= '*';
+			}
+			else
+			{
+				// Cycle through the "select" portion of the query and prep each column name.
+				// The reason we protect identifiers here rather than in the select() function
+				// is because until the user calls the from() function we don't know if there are aliases
+				foreach ($this->qb_select as $key => $val)
+				{
+					$no_escape = isset($this->qb_no_escape[$key]) ? $this->qb_no_escape[$key] : NULL;
+					$this->qb_select[$key] = $this->protect_identifiers($val, FALSE, $no_escape);
+				}
+
+				$sql .= implode(', ', $this->qb_select);
+			}
+		}
+
+		// Write the "FROM" portion of the query
+		if (count($this->qb_from) > 0)
+		{
+			$sql .= "\nFROM ".$this->_from_tables();
+		}
+
+		// Write the "JOIN" portion of the query
+		if (count($this->qb_join) > 0)
+		{
+			$sql .= "\n".implode("\n", $this->qb_join);
+		}
+
+		$sql .= $this->_compile_wh('qb_where')
+			.$this->_compile_group_by()
+			.$this->_compile_wh('qb_having')
+			.$this->_compile_order_by(); // ORDER BY
+
+		// LIMIT
+		if ($this->qb_limit OR $this->qb_offset)
+		{
+			return $this->_limit($sql."\n");
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Compile WHERE, HAVING statements
+	 *
+	 * Escapes identifiers in WHERE and HAVING statements at execution time.
+	 *
+	 * Required so that aliases are tracked properly, regardless of whether
+	 * where(), or_where(), having(), or_having are called prior to from(),
+	 * join() and dbprefix is added only if needed.
+	 *
+	 * @param	string	$qb_key	'qb_where' or 'qb_having'
+	 * @return	string	SQL statement
+	 */
+	protected function _compile_wh($qb_key)
+	{
+		if (count($this->$qb_key) > 0)
+		{
+			for ($i = 0, $c = count($this->$qb_key); $i < $c; $i++)
+			{
+				// Is this condition already compiled?
+				if (is_string($this->{$qb_key}[$i]))
+				{
+					continue;
+				}
+				elseif ($this->{$qb_key}[$i]['escape'] === FALSE)
+				{
+					$this->{$qb_key}[$i] = $this->{$qb_key}[$i]['condition'];
+					continue;
+				}
+
+				// Split multiple conditions
+				$conditions = preg_split(
+					'/((?:^|\s+)AND\s+|(?:^|\s+)OR\s+)/i',
+					$this->{$qb_key}[$i]['condition'],
+					-1,
+					PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY
+				);
+
+				for ($ci = 0, $cc = count($conditions); $ci < $cc; $ci++)
+				{
+					if (($op = $this->_get_operator($conditions[$ci])) === FALSE
+						OR ! preg_match('/^(\(?)(.*)('.preg_quote($op, '/').')\s*(.*(?<!\)))?(\)?)$/i', $conditions[$ci], $matches))
+					{
+						continue;
+					}
+
+					// $matches = array(
+					//	0 => '(test <= foo)',	/* the whole thing */
+					//	1 => '(',		/* optional */
+					//	2 => 'test',		/* the field name */
+					//	3 => ' <= ',		/* $op */
+					//	4 => 'foo',		/* optional, if $op is e.g. 'IS NULL' */
+					//	5 => ')'		/* optional */
+					// );
+
+					if ( ! empty($matches[4]))
+					{
+						$this->_is_literal($matches[4]) OR $matches[4] = $this->protect_identifiers(trim($matches[4]));
+						$matches[4] = ' '.$matches[4];
+					}
+
+					$conditions[$ci] = $matches[1].$this->protect_identifiers(trim($matches[2]))
+						.' '.trim($matches[3]).$matches[4].$matches[5];
+				}
+
+				$this->{$qb_key}[$i] = implode('', $conditions);
+			}
+
+			return ($qb_key === 'qb_having' ? "\nHAVING " : "\nWHERE ")
+				.implode("\n", $this->$qb_key);
+		}
+
+		return '';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Compile GROUP BY
+	 *
+	 * Escapes identifiers in GROUP BY statements at execution time.
+	 *
+	 * Required so that aliases are tracked properly, regardless of whether
+	 * group_by() is called prior to from(), join() and dbprefix is added
+	 * only if needed.
+	 *
+	 * @return	string	SQL statement
+	 */
+	protected function _compile_group_by()
+	{
+		if (count($this->qb_groupby) > 0)
+		{
+			for ($i = 0, $c = count($this->qb_groupby); $i < $c; $i++)
+			{
+				// Is it already compiled?
+				if (is_string($this->qb_groupby[$i]))
+				{
+					continue;
+				}
+
+				$this->qb_groupby[$i] = ($this->qb_groupby[$i]['escape'] === FALSE OR $this->_is_literal($this->qb_groupby[$i]['field']))
+					? $this->qb_groupby[$i]['field']
+					: $this->protect_identifiers($this->qb_groupby[$i]['field']);
+			}
+
+			return "\nGROUP BY ".implode(', ', $this->qb_groupby);
+		}
+
+		return '';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Compile ORDER BY
+	 *
+	 * Escapes identifiers in ORDER BY statements at execution time.
+	 *
+	 * Required so that aliases are tracked properly, regardless of whether
+	 * order_by() is called prior to from(), join() and dbprefix is added
+	 * only if needed.
+	 *
+	 * @return	string	SQL statement
+	 */
+	protected function _compile_order_by()
+	{
+		if (empty($this->qb_orderby))
+		{
+			return '';
+		}
+
+		for ($i = 0, $c = count($this->qb_orderby); $i < $c; $i++)
+		{
+			if (is_string($this->qb_orderby[$i]))
+			{
+				continue;
+			}
+
+			if ($this->qb_orderby[$i]['escape'] !== FALSE && ! $this->_is_literal($this->qb_orderby[$i]['field']))
+			{
+				$this->qb_orderby[$i]['field'] = $this->protect_identifiers($this->qb_orderby[$i]['field']);
+			}
+
+			$this->qb_orderby[$i] = $this->qb_orderby[$i]['field'].$this->qb_orderby[$i]['direction'];
+		}
+
+		return "\nORDER BY ".implode(', ', $this->qb_orderby);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Object to Array
+	 *
+	 * Takes an object as input and converts the class variables to array key/vals
+	 *
+	 * @param	object
+	 * @return	array
+	 */
+	protected function _object_to_array($object)
+	{
+		if ( ! is_object($object))
+		{
+			return $object;
+		}
+
+		$array = array();
+		foreach (get_object_vars($object) as $key => $val)
+		{
+			// There are some built in keys we need to ignore for this conversion
+			if ( ! is_object($val) && ! is_array($val) && $key !== '_parent_name')
+			{
+				$array[$key] = $val;
+			}
+		}
+
+		return $array;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Object to Array
+	 *
+	 * Takes an object as input and converts the class variables to array key/vals
+	 *
+	 * @param	object
+	 * @return	array
+	 */
+	protected function _object_to_array_batch($object)
+	{
+		if ( ! is_object($object))
+		{
+			return $object;
+		}
+
+		$array = array();
+		$out = get_object_vars($object);
+		$fields = array_keys($out);
+
+		foreach ($fields as $val)
+		{
+			// There are some built in keys we need to ignore for this conversion
+			if ($val !== '_parent_name')
+			{
+				$i = 0;
+				foreach ($out[$val] as $data)
+				{
+					$array[$i++][$val] = $data;
+				}
+			}
+		}
+
+		return $array;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Start Cache
+	 *
+	 * Starts QB caching
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function start_cache()
+	{
+		$this->qb_caching = TRUE;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Stop Cache
+	 *
+	 * Stops QB caching
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function stop_cache()
+	{
+		$this->qb_caching = FALSE;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Flush Cache
+	 *
+	 * Empties the QB cache
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function flush_cache()
+	{
+		$this->_reset_run(array(
+			'qb_cache_select'		=> array(),
+			'qb_cache_from'			=> array(),
+			'qb_cache_join'			=> array(),
+			'qb_cache_where'		=> array(),
+			'qb_cache_groupby'		=> array(),
+			'qb_cache_having'		=> array(),
+			'qb_cache_orderby'		=> array(),
+			'qb_cache_set'			=> array(),
+			'qb_cache_exists'		=> array(),
+			'qb_cache_no_escape'	=> array(),
+			'qb_cache_aliased_tables'	=> array()
+		));
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Merge Cache
+	 *
+	 * When called, this function merges any cached QB arrays with
+	 * locally called ones.
+	 *
+	 * @return	void
+	 */
+	protected function _merge_cache()
+	{
+		if (count($this->qb_cache_exists) === 0)
+		{
+			return;
+		}
+		elseif (in_array('select', $this->qb_cache_exists, TRUE))
+		{
+			$qb_no_escape = $this->qb_cache_no_escape;
+		}
+
+		foreach (array_unique($this->qb_cache_exists) as $val) // select, from, etc.
+		{
+			$qb_variable	= 'qb_'.$val;
+			$qb_cache_var	= 'qb_cache_'.$val;
+			$qb_new 	= $this->$qb_cache_var;
+
+			for ($i = 0, $c = count($this->$qb_variable); $i < $c; $i++)
+			{
+				if ( ! in_array($this->{$qb_variable}[$i], $qb_new, TRUE))
+				{
+					$qb_new[] = $this->{$qb_variable}[$i];
+					if ($val === 'select')
+					{
+						$qb_no_escape[] = $this->qb_no_escape[$i];
+					}
+				}
+			}
+
+			$this->$qb_variable = $qb_new;
+			if ($val === 'select')
+			{
+				$this->qb_no_escape = $qb_no_escape;
+			}
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Is literal
+	 *
+	 * Determines if a string represents a literal value or a field name
+	 *
+	 * @param	string	$str
+	 * @return	bool
+	 */
+	protected function _is_literal($str)
+	{
+		$str = trim($str);
+
+		if (empty($str) OR ctype_digit($str) OR (string) (float) $str === $str OR in_array(strtoupper($str), array('TRUE', 'FALSE'), TRUE))
+		{
+			return TRUE;
+		}
+
+		static $_str;
+
+		if (empty($_str))
+		{
+			$_str = ($this->_escape_char !== '"')
+				? array('"', "'") : array("'");
+		}
+
+		return in_array($str[0], $_str, TRUE);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Reset Query Builder values.
+	 *
+	 * Publicly-visible method to reset the QB values.
+	 *
+	 * @return	CI_DB_query_builder
+	 */
+	public function reset_query()
+	{
+		$this->_reset_select();
+		$this->_reset_write();
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Resets the query builder values.  Called by the get() function
+	 *
+	 * @param	array	An array of fields to reset
+	 * @return	void
+	 */
+	protected function _reset_run($qb_reset_items)
+	{
+		foreach ($qb_reset_items as $item => $default_value)
+		{
+			$this->$item = $default_value;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Resets the query builder values.  Called by the get() function
+	 *
+	 * @return	void
+	 */
+	protected function _reset_select()
+	{
+		$this->_reset_run(array(
+			'qb_select'		=> array(),
+			'qb_from'		=> array(),
+			'qb_join'		=> array(),
+			'qb_where'		=> array(),
+			'qb_groupby'		=> array(),
+			'qb_having'		=> array(),
+			'qb_orderby'		=> array(),
+			'qb_aliased_tables'	=> array(),
+			'qb_no_escape'		=> array(),
+			'qb_distinct'		=> FALSE,
+			'qb_limit'		=> FALSE,
+			'qb_offset'		=> FALSE
+		));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Resets the query builder "write" values.
+	 *
+	 * Called by the insert() update() insert_batch() update_batch() and delete() functions
+	 *
+	 * @return	void
+	 */
+	protected function _reset_write()
+	{
+		$this->_reset_run(array(
+			'qb_set'	=> array(),
+			'qb_set_ub'	=> array(),
+			'qb_from'	=> array(),
+			'qb_join'	=> array(),
+			'qb_where'	=> array(),
+			'qb_orderby'	=> array(),
+			'qb_keys'	=> array(),
+			'qb_limit'	=> FALSE
+		));
+	}
+
+}