Merge remote-tracking branch 'upstream/develop' into new_date

1 files changed, 2357 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..3ed556212
--- /dev/null
+++ b/system/database/DB_query_builder.php
@@ -0,0 +1,2357 @@
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 1.0
+ * @filesource
+ */
+
+/**
+ * Query Builder Class
+ *
+ * This is the platform-independent base Query Builder implementation class.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Drivers
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+
+abstract class CI_DB_query_builder extends CI_DB_driver {
+
+	protected $return_delete_sql		= FALSE;
+	protected $reset_delete_data		= FALSE;
+
+	protected $qb_select			= array();
+	protected $qb_distinct			= FALSE;
+	protected $qb_from			= array();
+	protected $qb_join			= array();
+	protected $qb_where			= array();
+	protected $qb_like			= array();
+	protected $qb_groupby			= array();
+	protected $qb_having			= array();
+	protected $qb_keys			= array();
+	protected $qb_limit			= FALSE;
+	protected $qb_offset			= FALSE;
+	protected $qb_order			= FALSE;
+	protected $qb_orderby			= array();
+	protected $qb_set			= array();
+	protected $qb_wherein			= array();
+	protected $qb_aliased_tables		= array();
+	protected $qb_store_array		= array();
+	protected $qb_where_group_started	= FALSE;
+	protected $qb_where_group_count		= 0;
+
+	// Query Builder Caching variables
+	protected $qb_caching				= FALSE;
+	protected $qb_cache_exists			= array();
+	protected $qb_cache_select			= array();
+	protected $qb_cache_from			= array();
+	protected $qb_cache_join			= array();
+	protected $qb_cache_where			= array();
+	protected $qb_cache_like			= array();
+	protected $qb_cache_groupby			= array();
+	protected $qb_cache_having			= array();
+	protected $qb_cache_orderby			= array();
+	protected $qb_cache_set				= array();
+
+	protected $qb_no_escape 			= array();
+	protected $qb_cache_no_escape			= array();
+
+	/**
+	 * Select
+	 *
+	 * Generates the SELECT portion of the query
+	 *
+	 * @param	string
+	 * @return	object
+	 */
+	public function select($select = '*', $escape = NULL)
+	{
+		if (is_string($select))
+		{
+			$select = explode(',', $select);
+		}
+
+		foreach ($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 $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Max
+	 *
+	 * Generates a SELECT MAX(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	object
+	 */
+	public function select_max($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'MAX');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Min
+	 *
+	 * Generates a SELECT MIN(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	object
+	 */
+	public function select_min($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'MIN');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Average
+	 *
+	 * Generates a SELECT AVG(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	object
+	 */
+	public function select_avg($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'AVG');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Select Sum
+	 *
+	 * Generates a SELECT SUM(field) portion of a query
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	object
+	 */
+	public function select_sum($select = '', $alias = '')
+	{
+		return $this->_max_min_avg_sum($select, $alias, 'SUM');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Processing Function for the four functions above:
+	 *
+	 *	select_max()
+	 *	select_min()
+	 *	select_avg()
+	 *	select_sum()
+	 *
+	 * @param	string	the field
+	 * @param	string	an alias
+	 * @return	object
+	 */
+	protected function _max_min_avg_sum($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 = $this->protect_identifiers($type.'('.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 $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Determines the alias name based on the table
+	 *
+	 * @param	string
+	 * @return	string
+	 */
+	protected function _create_alias_from_table($item)
+	{
+		if (strpos($item, '.') !== FALSE)
+		{
+			$item = explode('.', $item);
+			return end($item);
+		}
+
+		return $item;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * DISTINCT
+	 *
+	 * Sets a flag which tells the query string compiler to add DISTINCT
+	 *
+	 * @param	bool
+	 * @return	object
+	 */
+	public function distinct($val = TRUE)
+	{
+		$this->qb_distinct = is_bool($val) ? $val : TRUE;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * From
+	 *
+	 * Generates the FROM portion of the query
+	 *
+	 * @param	mixed	can be a string or array
+	 * @return	object
+	 */
+	public function from($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 $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Join
+	 *
+	 * Generates the JOIN portion of the query
+	 *
+	 * @param	string
+	 * @param	string	the join condition
+	 * @param	string	the type of join
+	 * @return	object
+	 */
+	public function join($table, $cond, $type = '')
+	{
+		if ($type !== '')
+		{
+			$type = strtoupper(trim($type));
+
+			if ( ! in_array($type, array('LEFT', 'RIGHT', 'OUTER', 'INNER', 'LEFT OUTER', 'RIGHT OUTER')))
+			{
+				$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);
+
+		// Strip apart the condition and protect the identifiers
+		if (preg_match('/([\[\w\.]+)([\W\s]+)(.+)/', $cond, $match))
+		{
+			$cond = $this->protect_identifiers($match[1]).$match[2].$this->protect_identifiers($match[3]);
+		}
+
+		// Assemble the JOIN statement
+		$this->qb_join[] = $join = $type.'JOIN '.$this->protect_identifiers($table, TRUE, NULL, FALSE).' ON '.$cond;
+
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_join[] = $join;
+			$this->qb_cache_exists[] = 'join';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where
+	 *
+	 * Generates the WHERE portion of the query. Separates
+	 * multiple calls with AND
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function where($key, $value = NULL, $escape = TRUE)
+	{
+		return $this->_where($key, $value, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR Where
+	 *
+	 * Generates the WHERE portion of the query. Separates
+	 * multiple calls with OR
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function or_where($key, $value = NULL, $escape = TRUE)
+	{
+		return $this->_where($key, $value, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where
+	 *
+	 * Called by where() or or_where()
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @param	string
+	 * @return	object
+	 */
+	protected function _where($key, $value = NULL, $type = 'AND ', $escape = NULL)
+	{
+		$type = $this->_group_get_type($type);
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		// If the escape value was not set will will base it on the global setting
+		if ( ! is_bool($escape))
+		{
+			$escape = $this->_protect_identifiers;
+		}
+
+		foreach ($key as $k => $v)
+		{
+			$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0) ? '' : $type;
+
+			if (is_null($v) && ! $this->_has_operator($k))
+			{
+				// value appears not to have been set, assign the test to IS NULL
+				$k .= ' IS NULL';
+			}
+
+			if ( ! is_null($v))
+			{
+				if ($escape === TRUE)
+				{
+					$k = $this->protect_identifiers($k, FALSE, $escape);
+					$v = ' '.$this->escape($v);
+				}
+
+				if ( ! $this->_has_operator($k))
+				{
+					$k .= ' = ';
+				}
+			}
+			else
+			{
+				$k = $this->protect_identifiers($k, FALSE, $escape);
+			}
+
+			$this->qb_where[] = $prefix.$k.$v;
+			if ($this->qb_caching === TRUE)
+			{
+				$this->qb_cache_where[] = $prefix.$k.$v;
+				$this->qb_cache_exists[] = 'where';
+			}
+
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where_in
+	 *
+	 * Generates a WHERE field IN ('item', 'item') SQL query joined with
+	 * AND if appropriate
+	 *
+	 * @param	string	The field to search
+	 * @param	array	The values searched on
+	 * @return	object
+	 */
+	public function where_in($key = NULL, $values = NULL)
+	{
+		return $this->_where_in($key, $values);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where_in_or
+	 *
+	 * Generates a WHERE field IN ('item', 'item') SQL query joined with
+	 * OR if appropriate
+	 *
+	 * @param	string	The field to search
+	 * @param	array	The values searched on
+	 * @return	object
+	 */
+	public function or_where_in($key = NULL, $values = NULL)
+	{
+		return $this->_where_in($key, $values, FALSE, 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where_not_in
+	 *
+	 * Generates a WHERE field NOT IN ('item', 'item') SQL query joined
+	 * with AND if appropriate
+	 *
+	 * @param	string	The field to search
+	 * @param	array	The values searched on
+	 * @return	object
+	 */
+	public function where_not_in($key = NULL, $values = NULL)
+	{
+		return $this->_where_in($key, $values, TRUE);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where_not_in_or
+	 *
+	 * Generates a WHERE field NOT IN ('item', 'item') SQL query joined
+	 * with OR if appropriate
+	 *
+	 * @param	string	The field to search
+	 * @param	array	The values searched on
+	 * @return	object
+	 */
+	public function or_where_not_in($key = NULL, $values = NULL)
+	{
+		return $this->_where_in($key, $values, TRUE, 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Where_in
+	 *
+	 * Called by where_in, where_in_or, where_not_in, where_not_in_or
+	 *
+	 * @param	string	The field to search
+	 * @param	array	The values searched on
+	 * @param	bool	If the statement would be IN or NOT IN
+	 * @param	string
+	 * @return	object
+	 */
+	protected function _where_in($key = NULL, $values = NULL, $not = FALSE, $type = 'AND ')
+	{
+		if ($key === NULL OR $values === NULL)
+		{
+			return;
+		}
+
+		$type = $this->_group_get_type($type);
+
+		if ( ! is_array($values))
+		{
+			$values = array($values);
+		}
+
+		$not = ($not) ? ' NOT' : '';
+
+		foreach ($values as $value)
+		{
+			$this->qb_wherein[] = $this->escape($value);
+		}
+
+		$prefix = (count($this->qb_where) === 0) ? '' : $type;
+		$this->qb_where[] = $where_in = $prefix.$this->protect_identifiers($key).$not.' IN ('.implode(', ', $this->qb_wherein).') ';
+
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_where[] = $where_in;
+			$this->qb_cache_exists[] = 'where';
+		}
+
+		// reset the array for multiple calls
+		$this->qb_wherein = array();
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Like
+	 *
+	 * Generates a %LIKE% portion of the query. Separates
+	 * multiple calls with AND
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function like($field, $match = '', $side = 'both')
+	{
+		return $this->_like($field, $match, 'AND ', $side);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Not Like
+	 *
+	 * Generates a NOT LIKE portion of the query. Separates
+	 * multiple calls with AND
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function not_like($field, $match = '', $side = 'both')
+	{
+		return $this->_like($field, $match, 'AND ', $side, 'NOT');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR Like
+	 *
+	 * Generates a %LIKE% portion of the query. Separates
+	 * multiple calls with OR
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function or_like($field, $match = '', $side = 'both')
+	{
+		return $this->_like($field, $match, 'OR ', $side);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OR Not Like
+	 *
+	 * Generates a NOT LIKE portion of the query. Separates
+	 * multiple calls with OR
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @return	object
+	 */
+	public function or_not_like($field, $match = '', $side = 'both')
+	{
+		return $this->_like($field, $match, 'OR ', $side, 'NOT');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Like
+	 *
+	 * Called by like() or orlike()
+	 *
+	 * @param	mixed
+	 * @param	mixed
+	 * @param	string
+	 * @return	object
+	 */
+	protected function _like($field, $match = '', $type = 'AND ', $side = 'both', $not = '')
+	{
+		$type = $this->_group_get_type($type);
+
+		if ( ! is_array($field))
+		{
+			$field = array($field => $match);
+		}
+
+		foreach ($field as $k => $v)
+		{
+			$k = $this->protect_identifiers($k);
+			$prefix = (count($this->qb_like) === 0) ? '' : $type;
+			$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 ($this->_like_escape_str !== '')
+			{
+				$like_statement = $like_statement.sprintf($this->_like_escape_str, $this->_like_escape_chr);
+			}
+
+			$this->qb_like[] = $like_statement;
+			if ($this->qb_caching === TRUE)
+			{
+				$this->qb_cache_like[] = $like_statement;
+				$this->qb_cache_exists[] = 'like';
+			}
+
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group.
+	 *
+	 * @param	string (Internal use only)
+	 * @param	string (Internal use only)
+	 * @return	object
+	 */
+	public function group_start($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;
+		$this->qb_where[] = $value = $prefix.$not.str_repeat(' ', ++$this->qb_where_group_count).' (';
+
+		if ($this->qb_caching)
+		{
+			$this->qb_cache_where[] = $value;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but ORs the group
+	 *
+	 * @return	object
+	 */
+	public function or_group_start()
+	{
+		return $this->group_start('', 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but NOTs the group
+	 *
+	 * @return	object
+	 */
+	public function not_group_start()
+	{
+		return $this->group_start('NOT ', 'AND ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Starts a query group, but OR NOTs the group
+	 *
+	 * @return	object
+	 */
+	public function or_not_group_start()
+	{
+		return $this->group_start('NOT ', 'OR ');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Ends a query group
+	 *
+	 * @return	object
+	 */
+	public function group_end()
+	{
+		$this->qb_where_group_started = FALSE;
+		$this->qb_where[] = $value = str_repeat(' ', $this->qb_where_group_count--) . ')';
+
+		if ($this->qb_caching)
+		{
+			$this->qb_cache_where[] = $value;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Group_get_type
+	 *
+	 * Called by group_start(), _like(), _where() and _where_in()
+	 *
+	 * @param	string
+	 * @return	string
+	 */
+	protected function _group_get_type($type)
+	{
+		if ($this->qb_where_group_started)
+		{
+			$type = '';
+			$this->qb_where_group_started = FALSE;
+		}
+
+		return $type;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * GROUP BY
+	 *
+	 * @param	string
+	 * @return	object
+	 */
+	public function group_by($by)
+	{
+		if (is_string($by))
+		{
+			$by = explode(',', $by);
+		}
+
+		foreach ($by as $val)
+		{
+			$val = trim($val);
+
+			if ($val !== '')
+			{
+				$this->qb_groupby[] = $val = $this->protect_identifiers($val);
+
+				if ($this->qb_caching === TRUE)
+				{
+					$this->qb_cache_groupby[] = $val;
+					$this->qb_cache_exists[] = 'groupby';
+				}
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the HAVING value
+	 *
+	 * Separates multiple calls with AND
+	 *
+	 * @param	string
+	 * @param	string
+	 * @return	object
+	 */
+	public function having($key, $value = '', $escape = TRUE)
+	{
+		return $this->_having($key, $value, 'AND ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the OR HAVING value
+	 *
+	 * Separates multiple calls with OR
+	 *
+	 * @param	string
+	 * @param	string
+	 * @return	object
+	 */
+	public function or_having($key, $value = '', $escape = TRUE)
+	{
+		return $this->_having($key, $value, 'OR ', $escape);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the HAVING values
+	 *
+	 * Called by having() or or_having()
+	 *
+	 * @param	string
+	 * @param	string
+	 * @return	object
+	 */
+	protected function _having($key, $value = '', $type = 'AND ', $escape = TRUE)
+	{
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		foreach ($key as $k => $v)
+		{
+			$prefix = (count($this->qb_having) === 0) ? '' : $type;
+
+			if ($escape === TRUE)
+			{
+				$k = $this->protect_identifiers($k);
+			}
+
+			if ( ! $this->_has_operator($k))
+			{
+				$k .= ' = ';
+			}
+
+			if ($v !== '')
+			{
+				$v = ' '.$this->escape($v);
+			}
+
+			$this->qb_having[] = $prefix.$k.$v;
+			if ($this->qb_caching === TRUE)
+			{
+				$this->qb_cache_having[] = $prefix.$k.$v;
+				$this->qb_cache_exists[] = 'having';
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the ORDER BY value
+	 *
+	 * @param	string
+	 * @param	string	direction: asc or desc
+	 * @param	bool	enable field name escaping
+	 * @return	object
+	 */
+	public function order_by($orderby, $direction = '', $escape = TRUE)
+	{
+		if (strtolower($direction) === 'random')
+		{
+			$orderby = ''; // Random results want or don't need a field name
+			$direction = $this->_random_keyword;
+		}
+		elseif (trim($direction) !== '')
+		{
+			$direction = (in_array(strtoupper(trim($direction)), array('ASC', 'DESC'), TRUE)) ? ' '.$direction : ' ASC';
+		}
+
+
+		if ((strpos($orderby, ',') !== FALSE) && $escape === TRUE)
+		{
+			$temp = array();
+			foreach (explode(',', $orderby) as $part)
+			{
+				$part = trim($part);
+				if ( ! in_array($part, $this->qb_aliased_tables))
+				{
+					$part = $this->protect_identifiers(trim($part));
+				}
+
+				$temp[] = $part;
+			}
+
+			$orderby = implode(', ', $temp);
+		}
+		elseif ($direction !== $this->_random_keyword)
+		{
+			if ($escape === TRUE)
+			{
+				$orderby = $this->protect_identifiers($orderby);
+			}
+		}
+
+		$this->qb_orderby[] = $orderby_statement = $orderby.$direction;
+
+		if ($this->qb_caching === TRUE)
+		{
+			$this->qb_cache_orderby[] = $orderby_statement;
+			$this->qb_cache_exists[] = 'orderby';
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the LIMIT value
+	 *
+	 * @param	int	the limit value
+	 * @param	int	the offset value
+	 * @return	object
+	 */
+	public function limit($value, $offset = NULL)
+	{
+		$this->qb_limit = (int) $value;
+
+		if ( ! is_null($offset))
+		{
+			$this->qb_offset = (int) $offset;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Sets the OFFSET value
+	 *
+	 * @param	int	the offset value
+	 * @return	object
+	 */
+	public function offset($offset)
+	{
+		$this->qb_offset = (int) $offset;
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set" function.  Allows key/value pairs to be set for inserting or updating
+	 *
+	 * @param	mixed
+	 * @param	string
+	 * @param	bool
+	 * @return	object
+	 */
+	public function set($key, $value = '', $escape = TRUE)
+	{
+		$key = $this->_object_to_array($key);
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		foreach ($key as $k => $v)
+		{
+			if ($escape === FALSE)
+			{
+				$this->qb_set[$this->protect_identifiers($k)] = $v;
+			}
+			else
+			{
+				$this->qb_set[$this->protect_identifiers($k, FALSE, TRUE)] = $this->escape($v);
+			}
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get SELECT query string
+	 *
+	 * Compiles a SELECT query string and returns the sql.
+	 *
+	 * @param	string	the table name to select from (optional)
+	 * @param	bool	TRUE: resets QB values; FALSE: leave QB vaules alone
+	 * @return	string
+	 */
+	public function get_compiled_select($table = '', $reset = TRUE)
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		$select =  $this->_compile_select();
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_select();
+		}
+
+		return $select;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get
+	 *
+	 * Compiles the select statement based on the other functions called
+	 * and runs the query
+	 *
+	 * @param	string	the table
+	 * @param	string	the limit clause
+	 * @param	string	the offset clause
+	 * @return	object
+	 */
+	public function get($table = '', $limit = null, $offset = null)
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		if ( ! is_null($limit))
+		{
+			$this->limit($limit, $offset);
+		}
+
+		$result = $this->query($this->_compile_select());
+		$this->_reset_select();
+		return $result;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * "Count All Results" query
+	 *
+	 * Generates a platform-specific query string that counts all records
+	 * returned by an Query Builder query.
+	 *
+	 * @param	string
+	 * @return	string
+	 */
+	public function count_all_results($table = '')
+	{
+		if ($table !== '')
+		{
+			$this->_track_aliases($table);
+			$this->from($table);
+		}
+
+		$result = $this->query($this->_compile_select($this->_count_string.$this->protect_identifiers('numrows')));
+		$this->_reset_select();
+
+		if ($result->num_rows() === 0)
+		{
+			return 0;
+		}
+
+		$row = $result->row();
+		return (int) $row->numrows;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get_Where
+	 *
+	 * Allows the where clause, limit and offset to be added directly
+	 *
+	 * @param	string	the where clause
+	 * @param	string	the limit clause
+	 * @param	string	the offset clause
+	 * @return	object
+	 */
+	public function get_where($table = '', $where = null, $limit = null, $offset = null)
+	{
+		if ($table !== '')
+		{
+			$this->from($table);
+		}
+
+		if ( ! is_null($where))
+		{
+			$this->where($where);
+		}
+
+		if ( ! is_null($limit))
+		{
+			$this->limit($limit, $offset);
+		}
+
+		$result = $this->query($this->_compile_select());
+		$this->_reset_select();
+		return $result;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert_Batch
+	 *
+	 * Compiles batch insert strings and runs the queries
+	 *
+	 * @param	string	the table to retrieve the results from
+	 * @param	array	an associative array of insert values
+	 * @return	object
+	 */
+	public function insert_batch($table = '', $set = NULL)
+	{
+		if ( ! is_null($set))
+		{
+			$this->set_insert_batch($set);
+		}
+
+		if (count($this->qb_set) === 0)
+		{
+			if ($this->db_debug)
+			{
+				// No valid data array. Folds in cases where keys and values did not match up
+				return $this->display_error('db_must_use_set');
+			}
+			return FALSE;
+		}
+
+		if ($table === '')
+		{
+			if ( ! isset($this->qb_from[0]))
+			{
+				return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+			}
+
+			$table = $this->qb_from[0];
+		}
+
+		// Batch this baby
+		for ($i = 0, $total = count($this->qb_set); $i < $total; $i += 100)
+		{
+			$this->query($this->_insert_batch($this->protect_identifiers($table, TRUE, NULL, FALSE), $this->qb_keys, array_slice($this->qb_set, $i, 100)));
+		}
+
+		$this->_reset_write();
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert_batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	the table name
+	 * @param	array	the insert keys
+	 * @param	array	the insert values
+	 * @return	string
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set_insert_batch" function.  Allows key/value pairs to be set for batch inserts
+	 *
+	 * @param	mixed
+	 * @param	string
+	 * @param	bool
+	 * @return	object
+	 */
+	public function set_insert_batch($key, $value = '', $escape = TRUE)
+	{
+		$key = $this->_object_to_array_batch($key);
+
+		if ( ! is_array($key))
+		{
+			$key = array($key => $value);
+		}
+
+		$keys = array_keys($this->_object_to_array(current($key)));
+		sort($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)
+			{
+				$this->qb_set[] =  '('.implode(',', $row).')';
+			}
+			else
+			{
+				$clean = array();
+				foreach ($row as $value)
+				{
+					$clean[] = $this->escape($value);
+				}
+
+				$this->qb_set[] =  '('.implode(',', $clean).')';
+			}
+		}
+
+		foreach ($keys as $k)
+		{
+			$this->qb_keys[] = $this->protect_identifiers($k);
+		}
+
+		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 $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert
+	 *
+	 * Compiles an insert string and runs the query
+	 *
+	 * @param	string	the table to insert data into
+	 * @param	array	an associative array of insert values
+	 * @return	object
+	 */
+	public function insert($table = '', $set = NULL)
+	{
+		if ( ! is_null($set))
+		{
+			$this->set($set);
+		}
+
+		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)
+		);
+
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @param	array	the insert keys
+	 * @param	array	the insert values
+	 * @return	string
+	 */
+	protected function _insert($table, $keys, $values)
+	{
+		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate Insert
+	 *
+	 * This method is used by both insert() and get_compiled_insert() to
+	 * validate that the there data is actually being set and that table
+	 * has been chosen to be inserted into.
+	 *
+	 * @param	string	the table to insert data into
+	 * @return	string
+	 */
+	protected function _validate_insert($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) ? $this->display_error('db_must_set_table') : FALSE;
+		}
+
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Replace
+	 *
+	 * Compiles an replace into string and runs the query
+	 *
+	 * @param	string	the table to replace data into
+	 * @param	array	an associative array of insert values
+	 * @return	object
+	 */
+	public function replace($table = '', $set = NULL)
+	{
+		if ( ! is_null($set))
+		{
+			$this->set($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(', ', $values).')';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * From Tables
+	 *
+	 * This public function implicitly groups FROM tables so there is no confusion
+	 * about operator precedence in harmony with SQL standards
+	 *
+	 * @param       array
+	 * @return      string
+	 */
+	protected function _from_tables($tables)
+	{
+		is_array($tables) OR $tables = array($tables);
+
+		return (count($tables) === 1) ? $tables[0] : '('.implode(', ', $tables).')';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Get UPDATE query string
+	 *
+	 * Compiles an update query and returns the sql
+	 *
+	 * @param	string	the table to update
+	 * @param	bool	TRUE: reset QB values; FALSE: leave QB values alone
+	 * @return	string
+	 */
+	public function get_compiled_update($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->protect_identifiers($this->qb_from[0], TRUE, NULL, FALSE), $this->qb_set, $this->qb_where, $this->qb_orderby, $this->qb_limit);
+
+		if ($reset === TRUE)
+		{
+			$this->_reset_write();
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update
+	 *
+	 * Compiles an update string and runs the query
+	 *
+	 * @param	string	the table to retrieve the results from
+	 * @param	array	an associative array of update values
+	 * @param	mixed	the where clause
+	 * @return	object
+	 */
+	public function update($table = '', $set = NULL, $where = NULL, $limit = NULL)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if ( ! is_null($set))
+		{
+			$this->set($set);
+		}
+
+		if ($this->_validate_update($table) === FALSE)
+		{
+			return FALSE;
+		}
+
+		if ($where !== NULL)
+		{
+			$this->where($where);
+		}
+
+		if ($limit != NULL)
+		{
+			$this->limit($limit);
+		}
+
+		$sql = $this->_update($this->protect_identifiers($this->qb_from[0], TRUE, NULL, FALSE), $this->qb_set, $this->qb_where, $this->qb_orderby, $this->qb_limit, $this->qb_like);
+
+		$this->_reset_write();
+		return $this->query($sql);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update statement
+	 *
+	 * Generates a platform-specific update string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @param	array	the update data
+	 * @param	array	the where clause
+	 * @param	array	the orderby clause
+	 * @param	array	the limit clause
+	 * @param	array	the like clause
+	 * @return	string
+	 */
+	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	{
+		foreach ($values as $key => $val)
+		{
+			$valstr[] = $key.' = '.$val;
+		}
+
+		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
+
+		if ( ! empty($like))
+		{
+			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
+		}
+
+		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
+			.$where
+			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '')
+			.($limit ? ' LIMIT '.$limit : '');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate Update
+	 *
+	 * This method is used by both update() and get_compiled_update() to
+	 * validate that data is actually being set and that a table has been
+	 * chosen to be update.
+	 *
+	 * @param	string	the table to update data on
+	 * @return	bool
+	 */
+	protected function _validate_update($table = '')
+	{
+		if (count($this->qb_set) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_set') : FALSE;
+		}
+
+		if ($table !== '')
+		{
+			$this->qb_from[0] = $table;
+		}
+		elseif ( ! isset($this->qb_from[0]))
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_set_table') : FALSE;
+		}
+
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update_Batch
+	 *
+	 * Compiles an update string and runs the query
+	 *
+	 * @param	string	the table to retrieve the results from
+	 * @param	array	an associative array of update values
+	 * @param	string	the where key
+	 * @return	bool
+	 */
+	public function update_batch($table = '', $set = NULL, $index = NULL)
+	{
+		// Combine any cached components with the current statements
+		$this->_merge_cache();
+
+		if (is_null($index))
+		{
+			return ($this->db_debug) ? $this->display_error('db_must_use_index') : FALSE;
+		}
+
+		if ( ! is_null($set))
+		{
+			$this->set_update_batch($set, $index);
+		}
+
+		if (count($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 = $this->qb_from[0];
+		}
+
+		// Batch this baby
+		for ($i = 0, $total = count($this->qb_set); $i < $total; $i += 100)
+		{
+			$this->query($this->_update_batch($this->protect_identifiers($table, TRUE, NULL, FALSE), array_slice($this->qb_set, $i, 100), $this->protect_identifiers($index), $this->qb_where));
+		}
+
+		$this->_reset_write();
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * The "set_update_batch" function.  Allows key/value pairs to be set for batch updating
+	 *
+	 * @param	array
+	 * @param	string
+	 * @param	bool
+	 * @return	object
+	 */
+	public function set_update_batch($key, $index = '', $escape = TRUE)
+	{
+		$key = $this->_object_to_array_batch($key);
+
+		if ( ! is_array($key))
+		{
+			// @todo error
+		}
+
+		foreach ($key as $k => $v)
+		{
+			$index_set = FALSE;
+			$clean = array();
+			foreach ($v as $k2 => $v2)
+			{
+				if ($k2 === $index)
+				{
+					$index_set = TRUE;
+				}
+
+				$clean[$this->protect_identifiers($k2)] = ($escape === FALSE) ? $v2 : $this->escape($v2);
+			}
+
+			if ($index_set === FALSE)
+			{
+				return $this->display_error('db_batch_missing_index');
+			}
+
+			$this->qb_set[] = $clean;
+		}
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Empty Table
+	 *
+	 * Compiles a delete string and runs "DELETE FROM table"
+	 *
+	 * @param	string	the table to empty
+	 * @return	object
+	 */
+	public function empty_table($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	object
+	 */
+	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 $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Delete
+	 *
+	 * Compiles a delete string and runs the query
+	 *
+	 * @param	mixed	the table(s) to delete from. String or array
+	 * @param	mixed	the where clause
+	 * @param	mixed	the limit clause
+	 * @param	bool
+	 * @return	object
+	 */
+	public function delete($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))
+		{
+			foreach ($table as $single_table)
+			{
+				$this->delete($single_table, $where, $limit, FALSE);
+			}
+
+			$this->_reset_write();
+			return;
+		}
+		else
+		{
+			$table = $this->protect_identifiers($table, TRUE, NULL, FALSE);
+		}
+
+		if ($where !== '')
+		{
+			$this->where($where);
+		}
+
+		if ($limit != NULL)
+		{
+			$this->limit($limit);
+		}
+
+		if (count($this->qb_where) === 0 && count($this->qb_wherein) === 0 && count($this->qb_like) === 0)
+		{
+			return ($this->db_debug) ? $this->display_error('db_del_must_use_where') : FALSE;
+		}
+
+		$sql = $this->_delete($table, $this->qb_where, $this->qb_like, $this->qb_limit);
+		if ($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
+	 * @param	array	the where clause
+	 * @param	array	the like clause
+	 * @param	string	the limit clause
+	 * @return	string
+	 */
+	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	{
+		$conditions = array();
+
+		empty($where) OR $conditions[] = implode(' ', $where);
+		empty($like) OR $conditions[] = implode(' ', $like);
+
+		return 'DELETE FROM '.$table
+			.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '')
+			.($limit ? ' LIMIT '.$limit : '');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * DB Prefix
+	 *
+	 * Prepends a database prefix if one exists in configuration
+	 *
+	 * @param	string	the table
+	 * @return	string
+	 */
+	public function dbprefix($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('/ AS /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))
+			{
+				$this->qb_aliased_tables[] = $table;
+			}
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Compile the SELECT statement
+	 *
+	 * Generates a query string based on which functions were used.
+	 * Should not be called directly.  The get() function calls it.
+	 *
+	 * @return	string
+	 */
+	protected function _compile_select($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)
+			{
+				$sql .= '*';
+			}
+			else
+			{
+				// Cycle through the "select" portion of the query and prep each column name.
+				// The reason we protect identifiers here rather then in the select() function
+				// is because until the user calls the from() function we don't know if there are aliases
+				foreach ($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($this->qb_from);
+		}
+
+		// Write the "JOIN" portion of the query
+		if (count($this->qb_join) > 0)
+		{
+			$sql .= "\n".implode("\n", $this->qb_join);
+		}
+
+		// Write the "WHERE" portion of the query
+		if (count($this->qb_where) > 0 OR count($this->qb_like) > 0)
+		{
+			$sql .= "\nWHERE ";
+		}
+
+		$sql .= implode("\n", $this->qb_where);
+
+		// Write the "LIKE" portion of the query
+		if (count($this->qb_like) > 0)
+		{
+			if (count($this->qb_where) > 0)
+			{
+				$sql .= "\nAND ";
+			}
+
+			$sql .= implode("\n", $this->qb_like);
+		}
+
+		// Write the "GROUP BY" portion of the query
+		if (count($this->qb_groupby) > 0)
+		{
+			$sql .= "\nGROUP BY ".implode(', ', $this->qb_groupby);
+		}
+
+		// Write the "HAVING" portion of the query
+		if (count($this->qb_having) > 0)
+		{
+			$sql .= "\nHAVING ".implode("\n", $this->qb_having);
+		}
+
+		// Write the "ORDER BY" portion of the query
+		if (count($this->qb_orderby) > 0)
+		{
+			$sql .= "\nORDER BY ".implode(', ', $this->qb_orderby);
+			if ($this->qb_order !== FALSE)
+			{
+				$sql .= ($this->qb_order === 'desc') ? ' DESC' : ' ASC';
+			}
+		}
+
+		// Write the "LIMIT" portion of the query
+		if (is_numeric($this->qb_limit))
+		{
+			return $this->_limit($sql."\n", $this->qb_limit, $this->qb_offset);
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Object to Array
+	 *
+	 * Takes an object as input and converts the class variables to array key/vals
+	 *
+	 * @param	object
+	 * @return	array
+	 */
+	protected function _object_to_array($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	void
+	 */
+	public function start_cache()
+	{
+		$this->qb_caching = TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Stop Cache
+	 *
+	 * Stops QB caching
+	 *
+	 * @return	void
+	 */
+	public function stop_cache()
+	{
+		$this->qb_caching = FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Flush Cache
+	 *
+	 * Empties the QB cache
+	 *
+	 * @return	void
+	 */
+	public function flush_cache()
+	{
+		$this->_reset_run(array(
+			'qb_cache_select'		=> array(),
+			'qb_cache_from'			=> array(),
+			'qb_cache_join'			=> array(),
+			'qb_cache_where'		=> array(),
+			'qb_cache_like'			=> array(),
+			'qb_cache_groupby'		=> array(),
+			'qb_cache_having'		=> array(),
+			'qb_cache_orderby'		=> array(),
+			'qb_cache_set'			=> array(),
+			'qb_cache_exists'		=> array(),
+			'qb_cache_no_escape'	=> array()
+		));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Merge Cache
+	 *
+	 * When called, this function merges any cached QB arrays with
+	 * locally called ones.
+	 *
+	 * @return	void
+	 */
+	protected function _merge_cache()
+	{
+		if (count($this->qb_cache_exists) === 0)
+		{
+			return;
+		}
+
+		foreach ($this->qb_cache_exists as $val)
+		{
+			$qb_variable	= 'qb_'.$val;
+			$qb_cache_var	= 'qb_cache_'.$val;
+
+			if (count($this->$qb_cache_var) === 0)
+			{
+				continue;
+			}
+
+			$this->$qb_variable = array_unique(array_merge($this->$qb_cache_var, $this->$qb_variable));
+		}
+
+		// If we are "protecting identifiers" we need to examine the "from"
+		// portion of the query to determine if there are any aliases
+		if ($this->_protect_identifiers === TRUE && count($this->qb_cache_from) > 0)
+		{
+			$this->_track_aliases($this->qb_from);
+		}
+
+		$this->qb_no_escape = $this->qb_cache_no_escape;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Reset Query Builder values.
+	 *
+	 * Publicly-visible method to reset the QB values.
+	 *
+	 * @return	void
+	 */
+	public function reset_query()
+	{
+		$this->_reset_select();
+		$this->_reset_write();
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Resets the query builder values.  Called by the get() function
+	 *
+	 * @param	array	An array of fields to reset
+	 * @return	void
+	 */
+	protected function _reset_run($qb_reset_items)
+	{
+		foreach ($qb_reset_items as $item => $default_value)
+		{
+			if ( ! in_array($item, $this->qb_store_array))
+			{
+				$this->$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_like'		=> array(),
+					'qb_groupby'		=> array(),
+					'qb_having'		=> array(),
+					'qb_orderby'		=> array(),
+					'qb_wherein'		=> array(),
+					'qb_aliased_tables'	=> array(),
+					'qb_no_escape'		=> array(),
+					'qb_distinct'		=> FALSE,
+					'qb_limit'		=> FALSE,
+					'qb_offset'		=> FALSE,
+					'qb_order'		=> 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_from'	=> array(),
+			'qb_where'	=> array(),
+			'qb_like'	=> array(),
+			'qb_orderby'	=> array(),
+			'qb_keys'	=> array(),
+			'qb_limit'	=> FALSE,
+			'qb_order'	=> FALSE
+			)
+		);
+	}
+
+}
+
+/* End of file DB_query_builder.php */
+/* Location: ./system/database/DB_query_builder.php */
\ No newline at end of file