CI_DB_query_builder

Complexity

Total Complexity

327

Size/Duplication

Total Lines	2697
Duplicated Lines	5.38 %

Coupling/Cohesion

Components	1
Dependencies	1

Importance

Changes	7
Bugs	7	Features	0

80 Methods

Rating	Name	Duplication	Size	Complexity
B	select()	0	30	6
A	select_max()	0	4	1
A	select_min()	0	4	1
A	select_avg()	0	4	1
A	select_sum()	0	4	1
B	_max_min_avg_sum()	0	32	6
A	_create_alias_from_table()	0	10	2
A	distinct()	0	5	2
B	from()	10	40	6
D	join()	0	74	14
A	where()	0	4	1
A	or_where()	0	4	1
F	_wh()	0	51	14
A	where_in()	0	4	1
A	or_where_in()	0	4	1
A	where_not_in()	0	4	1
A	or_where_not_in()	0	4	1
D	_where_in()	0	47	11
A	like()	0	4	1
A	not_like()	0	4	1
A	or_like()	0	4	1
A	or_not_like()	0	4	1
D	_like()	0	54	13
A	group_start()	0	19	4
A	or_group_start()	0	4	1
A	not_group_start()	0	4	1
A	or_not_group_start()	0	4	1
A	group_end()	0	16	2
A	_group_get_type()	0	10	2
C	group_by()	0	30	7
A	having()	0	4	1
A	or_having()	0	4	1
C	order_by()	0	48	12
A	limit()	0	7	3
A	offset()	0	5	2
A	_limit()	0	4	2
B	set()	0	19	5
A	get_compiled_select()	0	17	3
A	get()	0	17	3
B	count_all_results()	0	25	6
A	get_where()	0	21	4
C	insert_batch()	19	34	8
A	_insert_batch()	0	4	1
C	set_insert_batch()	0	47	9
A	get_compiled_insert()	0	22	3
A	insert()	0	23	3
B	_validate_insert()	12	18	6
C	replace()	13	27	7
A	_replace()	0	4	1
A	_from_tables()	0	4	1
A	get_compiled_update()	0	19	3
B	update()	0	29	5
B	_validate_update()	4	18	6
D	update_batch()	19	42	10
B	_update_batch()	28	28	5
C	set_update_batch()	0	35	8
A	empty_table()	20	20	4
A	truncate()	20	20	4
A	_truncate()	0	4	1
A	get_compiled_delete()	0	7	1
C	delete()	0	53	13
A	_delete()	0	5	2
A	dbprefix()	0	9	2
A	set_dbprefix()	0	4	1
B	_track_aliases()	0	34	6
C	_compile_select()	0	58	9
C	_compile_wh()	0	61	11
B	_compile_group_by()	0	22	6
C	_compile_order_by()	0	23	7
B	_object_to_array()	0	19	6
B	_object_to_array_batch()	0	26	5
A	start_cache()	0	5	1
A	stop_cache()	0	5	1
A	flush_cache()	0	17	1
D	_merge_cache()	0	43	10
B	_is_literal()	0	19	7
A	reset_query()	0	6	1
A	_reset_run()	0	7	2
A	_reset_select()	0	17	1
A	_reset_write()	0	12	1

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 52 and the first side effect is on line 38.

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, 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. (http://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	http://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		http://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 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 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;

		// Split multiple conditions
		if ($escape === TRUE && preg_match_all('/\sAND\s|\sOR\s/i', $cond, $m, PREG_OFFSET_CAPTURE))
		{
			$newcond = '';
			$m[0][] = array('', strlen($cond));

			for ($i = 0, $c = count($m[0]), $s = 0;
				$i < $c;
				$s = $m[0][$i][1] + strlen($m[0][$i][0]), $i++)
			{
				$temp = substr($cond, $s, ($m[0][$i][1] - $s));

				$newcond .= preg_match("/([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $temp, $match)
						? $this->protect_identifiers($match[1]).$match[2].$this->protect_identifiers($match[3])
						: $temp;

				$newcond .= $m[0][$i][0];
			}

			$cond = ' ON '.$newcond;
		}
		// Split apart the condition and protect the identifiers
		elseif ($escape === TRUE && preg_match("/([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $cond, $match))
		{
			$cond = ' ON '.$this->protect_identifiers($match[1]).$match[2].$this->protect_identifiers($match[3]);
		}
		elseif ( ! $this->_has_operator($cond))
		{
			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
		}
		else
		{
			$cond = ' ON '.$cond;
		}

		// 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
				$k .= ' IS NULL';
			}
			elseif (preg_match('/\s*(!?=|<>|IS(?:\s+NOT)?)\s*$/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	$escape
	 * @return	object
	 */
	public function having($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	$escape
	 * @return	object
	 */
	public function or_having($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 ? $this->qb_offset.', ' : '').$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	object
	 */
	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);
		}

		$result = ($this->qb_distinct === TRUE OR ! empty($this->qb_orderby))
			? $this->query($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 ($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	$offset
	 * @return	object
	 */
	public function get_where($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, $escape = NULL)
	{
		if ($set !== NULL)
		{
			$this->set_insert_batch($set, '', $escape);
		}

		if (count($this->qb_set) === 0)
		{
			// No valid data array. Folds in cases where keys and values did not match up
			return ($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
		$affected_rows = 0;
		for ($i = 0, $total = count($this->qb_set); $i < $total; $i += 100)
		{
			$this->query($this->_insert_batch($this->protect_identifiers($table, TRUE, $escape, FALSE), $this->qb_keys, array_slice($this->qb_set, $i, 100)));
			$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(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)
			{
				$clean = array();
				foreach ($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	$escape	Whether to escape values and identifiers
	 * @return	object
	 */
	public function insert($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	object
	 */
	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	$limit
	 * @return	object
	 */
	public function update($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)
	{
		// 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)
		{
			$this->set_update_batch($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
		$affected_rows = 0;
		for ($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)));
			$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];

			foreach (array_keys($val) as $field)
			{
				if ($field !== $index)
				{
					$final[$field][] = 'WHEN '.$index.' = '.$val[$index].' THEN '.$val[$field];
				}
			}
		}

		$cases = '';
		foreach ($final as $k => $v)
		{
			$cases .= $k." = CASE \n"
				.implode("\n", $v)."\n"
				.'ELSE '.$k.' END, ';
		}

		$this->where($index.' 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;
				}

				$clean[$this->protect_identifiers($k2, FALSE, $escape)] = ($escape === FALSE) ? $v2 : $this->escape($v2);
			}

			if ($index_set === FALSE)
			{
				return $this->display_error('db_batch_missing_index');

The expression $this->display_error('db_batch_missing_index'); of type string|null adds the type string to the return on line 1969 which is incompatible with the return type documented by CI_DB_query_builder::set_update_batch of type CI_DB_query_builder|null.

			}

			$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	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))
			{
				$this->qb_aliased_tables[] = $table;
			}
		}
	}

	// --------------------------------------------------------------------

	/**
	 * 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)
		{
			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 wether
	 * 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(

43% of this comment could be valid code. Did you maybe forget this after debugging?

					//	0 => '(test <= foo)',	/* the whole thing */
					//	1 => '(',		/* optional */
					//	2 => 'test',		/* the field name */
					//	3 => ' <= ',		/* $op */

42% of this comment could be valid code. Did you maybe forget this after debugging?

					//	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 wether
	 * 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 wether
	 * 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 (is_array($this->qb_orderby) && count($this->qb_orderby) > 0)
		{
			for ($i = 0, $c = count($this->qb_orderby); $i < $c; $i++)
			{
				if ($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 $this->qb_orderby = "\nORDER BY ".implode(', ', $this->qb_orderby);
		}
		elseif (is_string($this->qb_orderby))
		{
			return $this->qb_orderby;
		}

		return '';
	}

	// --------------------------------------------------------------------

	/**
	 * 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()
		));

		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;
			}
		}

		// 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);
		}
	}

	// --------------------------------------------------------------------

	/**
	 * 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_from'	=> array(),
			'qb_join'	=> array(),
			'qb_where'	=> array(),
			'qb_orderby'	=> array(),
			'qb_keys'	=> array(),
			'qb_limit'	=> FALSE
		));
	}

}