system/database/drivers/mysqli/mysqli_driver.php - code-igniter-v3-giggi - Gitiles

 <?php
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP
  *
  * This content is released under the MIT License (MIT)
  *
  * Copyright (c) 2014 - 2018, British Columbia Institute of Technology
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
  * @copyright	Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
  * @link	https://codeigniter.com
  * @since	Version 1.3.0
  * @filesource
  */
 defined('BASEPATH') OR exit('No direct script access allowed');

 /**
  * MySQLi Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
  * creates dynamically based on whether the query builder
  * class is being used or not.
  *
  * @package		CodeIgniter
  * @subpackage	Drivers
  * @category	Database
  * @author		EllisLab Dev Team
  * @link		https://codeigniter.com/user_guide/database/
  */
 class CI_DB_mysqli_driver extends CI_DB {

 	/**
 	 * Database driver
 	 *
 	 * @var	string
 	 */
 	public $dbdriver = 'mysqli';

 	/**
 	 * Compression flag
 	 *
 	 * @var	bool
 	 */
 	public $compress = FALSE;

 	/**
 	 * DELETE hack flag
 	 *
 	 * Whether to use the MySQL "delete hack" which allows the number
 	 * of affected rows to be shown. Uses a preg_replace when enabled,
 	 * adding a bit more processing to all queries.
 	 *
 	 * @var	bool
 	 */
 	public $delete_hack = TRUE;

 	/**
 	 * Strict ON flag
 	 *
 	 * Whether we're running in strict SQL mode.
 	 *
 	 * @var	bool
 	 */
 	public $stricton;

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

 	/**
 	 * Identifier escape character
 	 *
 	 * @var	string
 	 */
 	protected $_escape_char = '`';

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

 	/**
 	 * MySQLi object
 	 *
 	 * Has to be preserved without being assigned to $conn_id.
 	 *
 	 * @var	MySQLi
 	 */
 	protected $_mysqli;

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

 	/**
 	 * Database connection
 	 *
 	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
 	{
 		// Do we have a socket path?
 		if ($this->hostname[0] === '/')
 		{
 			$hostname = NULL;
 			$port = NULL;
 			$socket = $this->hostname;
 		}
 		else
 		{
 			$hostname = ($persistent === TRUE)
 				? 'p:'.$this->hostname : $this->hostname;
 			$port = empty($this->port) ? NULL : $this->port;
 			$socket = NULL;
 		}

 		$client_flags = ($this->compress === TRUE) ? MYSQLI_CLIENT_COMPRESS : 0;
 		$this->_mysqli = mysqli_init();

 		$this->_mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 10);

 		if (isset($this->stricton))
 		{
 			if ($this->stricton)
 			{
 				$this->_mysqli->options(MYSQLI_INIT_COMMAND, 'SET SESSION sql_mode = CONCAT(@@sql_mode, ",", "STRICT_ALL_TABLES")');
 			}
 			else
 			{
 				$this->_mysqli->options(MYSQLI_INIT_COMMAND,
 					'SET SESSION sql_mode =
 					REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
 					@@sql_mode,
 					"STRICT_ALL_TABLES,", ""),
 					",STRICT_ALL_TABLES", ""),
 					"STRICT_ALL_TABLES", ""),
 					"STRICT_TRANS_TABLES,", ""),
 					",STRICT_TRANS_TABLES", ""),
 					"STRICT_TRANS_TABLES", "")'
 				);
 			}
 		}

 		if (is_array($this->encrypt))
 		{
 			$ssl = array();
 			empty($this->encrypt['ssl_key'])    OR $ssl['key']    = $this->encrypt['ssl_key'];
 			empty($this->encrypt['ssl_cert'])   OR $ssl['cert']   = $this->encrypt['ssl_cert'];
 			empty($this->encrypt['ssl_ca'])     OR $ssl['ca']     = $this->encrypt['ssl_ca'];
 			empty($this->encrypt['ssl_capath']) OR $ssl['capath'] = $this->encrypt['ssl_capath'];
 			empty($this->encrypt['ssl_cipher']) OR $ssl['cipher'] = $this->encrypt['ssl_cipher'];

 			if ( ! empty($ssl))
 			{
 				if (isset($this->encrypt['ssl_verify']))
 				{
 					if ($this->encrypt['ssl_verify'])
 					{
 						defined('MYSQLI_OPT_SSL_VERIFY_SERVER_CERT') && $this->_mysqli->options(MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, TRUE);
 					}
 					// Apparently (when it exists), setting MYSQLI_OPT_SSL_VERIFY_SERVER_CERT
 					// to FALSE didn't do anything, so PHP 5.6.16 introduced yet another
 					// constant ...
 					//
 					// https://secure.php.net/ChangeLog-5.php#5.6.16
 					// https://bugs.php.net/bug.php?id=68344
 					elseif (defined('MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT'))
 					{
 						$client_flags |= MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT;
 					}
 				}

 				$client_flags |= MYSQLI_CLIENT_SSL;
 				$this->_mysqli->ssl_set(
 					isset($ssl['key'])    ? $ssl['key']    : NULL,
 					isset($ssl['cert'])   ? $ssl['cert']   : NULL,
 					isset($ssl['ca'])     ? $ssl['ca']     : NULL,
 					isset($ssl['capath']) ? $ssl['capath'] : NULL,
 					isset($ssl['cipher']) ? $ssl['cipher'] : NULL
 				);
 			}
 		}

 		if ($this->_mysqli->real_connect($hostname, $this->username, $this->password, $this->database, $port, $socket, $client_flags))
 		{
 			// Prior to version 5.7.3, MySQL silently downgrades to an unencrypted connection if SSL setup fails
 			if (
 				($client_flags & MYSQLI_CLIENT_SSL)
 				&& version_compare($this->_mysqli->client_info, '5.7.3', '<=')
 				&& empty($this->_mysqli->query("SHOW STATUS LIKE 'ssl_cipher'")->fetch_object()->Value)
 			)
 			{
 				$this->_mysqli->close();
 				$message = 'MySQLi was configured for an SSL connection, but got an unencrypted connection instead!';
 				log_message('error', $message);
 				return ($this->db_debug) ? $this->display_error($message, '', TRUE) : FALSE;
 			}

 			return $this->_mysqli;
 		}

 		return FALSE;
 	}

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

 	/**
 	 * Reconnect
 	 *
 	 * Keep / reestablish the db connection if no queries have been
 	 * sent for a length of time exceeding the server's idle timeout
 	 *
 	 * @return	void
 	 */
 	public function reconnect()
 	{
 		if ($this->conn_id !== FALSE && $this->conn_id->ping() === FALSE)
 		{
 			$this->conn_id = FALSE;
 		}
 	}

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

 	/**
 	 * Select the database
 	 *
 	 * @param	string	$database
 	 * @return	bool
 	 */
 	public function db_select($database = '')
 	{
 		if ($database === '')
 		{
 			$database = $this->database;
 		}

 		if ($this->conn_id->select_db($database))
 		{
 			$this->database = $database;
 			$this->data_cache = array();
 			return TRUE;
 		}

 		return FALSE;
 	}

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

 	/**
 	 * Set client character set
 	 *
 	 * @param	string	$charset
 	 * @return	bool
 	 */
 	protected function _db_set_charset($charset)
 	{
 		return $this->conn_id->set_charset($charset);
 	}

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

 	/**
 	 * Database version number
 	 *
 	 * @return	string
 	 */
 	public function version()
 	{
 		if (isset($this->data_cache['version']))
 		{
 			return $this->data_cache['version'];
 		}

 		return $this->data_cache['version'] = $this->conn_id->server_info;
 	}

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

 	/**
 	 * Execute the query
 	 *
 	 * @param	string	$sql	an SQL query
 	 * @return	mixed
 	 */
 	protected function _execute($sql)
 	{
 		return $this->conn_id->query($this->_prep_query($sql));
 	}

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

 	/**
 	 * Prep the query
 	 *
 	 * If needed, each database adapter can prep the query string
 	 *
 	 * @param	string	$sql	an SQL query
 	 * @return	string
 	 */
 	protected function _prep_query($sql)
 	{
 		// mysqli_affected_rows() returns 0 for "DELETE FROM TABLE" queries. This hack
 		// modifies the query so that it a proper number of affected rows is returned.
 		if ($this->delete_hack === TRUE && preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
 		{
 			return trim($sql).' WHERE 1=1';
 		}

 		return $sql;
 	}

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

 	/**
 	 * Begin Transaction
 	 *
 	 * @return	bool
 	 */
 	protected function _trans_begin()
 	{
 		$this->conn_id->autocommit(FALSE);
 		return is_php('5.5')
 			? $this->conn_id->begin_transaction()
 			: $this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
 	}

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

 	/**
 	 * Commit Transaction
 	 *
 	 * @return	bool
 	 */
 	protected function _trans_commit()
 	{
 		if ($this->conn_id->commit())
 		{
 			$this->conn_id->autocommit(TRUE);
 			return TRUE;
 		}

 		return FALSE;
 	}

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

 	/**
 	 * Rollback Transaction
 	 *
 	 * @return	bool
 	 */
 	protected function _trans_rollback()
 	{
 		if ($this->conn_id->rollback())
 		{
 			$this->conn_id->autocommit(TRUE);
 			return TRUE;
 		}

 		return FALSE;
 	}

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

 	/**
 	 * Platform-dependent string escape
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	protected function _escape_str($str)
 	{
 		return $this->conn_id->real_escape_string($str);
 	}

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

 	/**
 	 * Affected Rows
 	 *
 	 * @return	int
 	 */
 	public function affected_rows()
 	{
 		return $this->conn_id->affected_rows;
 	}

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

 	/**
 	 * Insert ID
 	 *
 	 * @return	int
 	 */
 	public function insert_id()
 	{
 		return $this->conn_id->insert_id;
 	}

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

 	/**
 	 * List table query
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
 	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
 	{
 		$sql = 'SHOW TABLES FROM '.$this->escape_identifiers($this->database);

 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
 			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}

 		return $sql;
 	}

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

 	/**
 	 * Show column query
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
 	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
 	{
 		return 'SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE);
 	}

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

 	/**
 	 * Returns an object with field data
 	 *
 	 * @param	string	$table
 	 * @return	array
 	 */
 	public function field_data($table)
 	{
 		if (($query = $this->query('SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE))) === FALSE)
 		{
 			return FALSE;
 		}
 		$query = $query->result_object();

 		$retval = array();
 		for ($i = 0, $c = count($query); $i < $c; $i++)
 		{
 			$retval[$i]			= new stdClass();
 			$retval[$i]->name		= $query[$i]->Field;

 			sscanf($query[$i]->Type, '%[a-z](%d)',
 				$retval[$i]->type,
 				$retval[$i]->max_length
 			);

 			$retval[$i]->default		= $query[$i]->Default;
 			$retval[$i]->primary_key	= (int) ($query[$i]->Key === 'PRI');
 		}

 		return $retval;
 	}

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

 	/**
 	 * Error
 	 *
 	 * Returns an array containing code and message of the last
 	 * database error that has occurred.
 	 *
 	 * @return	array
 	 */
 	public function error()
 	{
 		if ( ! empty($this->_mysqli->connect_errno))
 		{
 			return array(
 				'code'    => $this->_mysqli->connect_errno,
 				'message' => $this->_mysqli->connect_error
 			);
 		}

 		return array('code' => $this->conn_id->errno, 'message' => $this->conn_id->error);
 	}

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

 	/**
 	 * FROM tables
 	 *
 	 * Groups tables in FROM clauses if needed, so there is no confusion
 	 * about operator precedence.
 	 *
 	 * @return	string
 	 */
 	protected function _from_tables()
 	{
 		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
 		{
 			return '('.implode(', ', $this->qb_from).')';
 		}

 		return implode(', ', $this->qb_from);
 	}

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

 	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
 	 */
 	protected function _close()
 	{
 		$this->conn_id->close();
 	}

 }
	<?php
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP
	*
	* This content is released under the MIT License (MIT)
	*
	* Copyright (c) 2014 - 2018, British Columbia Institute of Technology
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*
	* @package CodeIgniter
	* @author EllisLab Dev Team
	* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
	* @copyright Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
	* @license http://opensource.org/licenses/MIT MIT License
	* @link https://codeigniter.com
	* @since Version 1.3.0
	* @filesource
	*/
	defined('BASEPATH') OR exit('No direct script access allowed');

	/**
	* MySQLi Database Adapter Class
	*
	* Note: _DB is an extender class that the app controller
	* creates dynamically based on whether the query builder
	* class is being used or not.
	*
	* @package CodeIgniter
	* @subpackage Drivers
	* @category Database
	* @author EllisLab Dev Team
	* @link https://codeigniter.com/user_guide/database/
	*/
	class CI_DB_mysqli_driver extends CI_DB {

	/**
	* Database driver
	*
	* @var string
	*/
	public $dbdriver = 'mysqli';

	/**
	* Compression flag
	*
	* @var bool
	*/
	public $compress = FALSE;

	/**
	* DELETE hack flag
	*
	* Whether to use the MySQL "delete hack" which allows the number
	* of affected rows to be shown. Uses a preg_replace when enabled,
	* adding a bit more processing to all queries.
	*
	* @var bool
	*/
	public $delete_hack = TRUE;

	/**
	* Strict ON flag
	*
	* Whether we're running in strict SQL mode.
	*
	* @var bool
	*/
	public $stricton;

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

	/**
	* Identifier escape character
	*
	* @var string
	*/
	protected $_escape_char = '`';

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

	/**
	* MySQLi object
	*
	* Has to be preserved without being assigned to $conn_id.
	*
	* @var MySQLi
	*/
	protected $_mysqli;

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

	/**
	* Database connection
	*
	* @param bool $persistent
	* @return object
	*/
	public function db_connect($persistent = FALSE)
	{
	// Do we have a socket path?
	if ($this->hostname[0] === '/')
	{
	$hostname = NULL;
	$port = NULL;
	$socket = $this->hostname;
	}
	else
	{
	$hostname = ($persistent === TRUE)
	? 'p:'.$this->hostname : $this->hostname;
	$port = empty($this->port) ? NULL : $this->port;
	$socket = NULL;
	}

	$client_flags = ($this->compress === TRUE) ? MYSQLI_CLIENT_COMPRESS : 0;
	$this->_mysqli = mysqli_init();

	$this->_mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 10);

	if (isset($this->stricton))
	{
	if ($this->stricton)
	{
	$this->_mysqli->options(MYSQLI_INIT_COMMAND, 'SET SESSION sql_mode = CONCAT(@@sql_mode, ",", "STRICT_ALL_TABLES")');
	}
	else
	{
	$this->_mysqli->options(MYSQLI_INIT_COMMAND,
	'SET SESSION sql_mode =
	REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
	@@sql_mode,
	"STRICT_ALL_TABLES,", ""),
	",STRICT_ALL_TABLES", ""),
	"STRICT_ALL_TABLES", ""),
	"STRICT_TRANS_TABLES,", ""),
	",STRICT_TRANS_TABLES", ""),
	"STRICT_TRANS_TABLES", "")'
	);
	}
	}

	if (is_array($this->encrypt))
	{
	$ssl = array();
	empty($this->encrypt['ssl_key']) OR $ssl['key'] = $this->encrypt['ssl_key'];
	empty($this->encrypt['ssl_cert']) OR $ssl['cert'] = $this->encrypt['ssl_cert'];
	empty($this->encrypt['ssl_ca']) OR $ssl['ca'] = $this->encrypt['ssl_ca'];
	empty($this->encrypt['ssl_capath']) OR $ssl['capath'] = $this->encrypt['ssl_capath'];
	empty($this->encrypt['ssl_cipher']) OR $ssl['cipher'] = $this->encrypt['ssl_cipher'];

	if ( ! empty($ssl))
	{
	if (isset($this->encrypt['ssl_verify']))
	{
	if ($this->encrypt['ssl_verify'])
	{
	defined('MYSQLI_OPT_SSL_VERIFY_SERVER_CERT') && $this->_mysqli->options(MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, TRUE);
	}
	// Apparently (when it exists), setting MYSQLI_OPT_SSL_VERIFY_SERVER_CERT
	// to FALSE didn't do anything, so PHP 5.6.16 introduced yet another
	// constant ...
	//
	// https://secure.php.net/ChangeLog-5.php#5.6.16
	// https://bugs.php.net/bug.php?id=68344
	elseif (defined('MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT'))
	{
	$client_flags \|= MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT;
	}
	}

	$client_flags \|= MYSQLI_CLIENT_SSL;
	$this->_mysqli->ssl_set(
	isset($ssl['key']) ? $ssl['key'] : NULL,
	isset($ssl['cert']) ? $ssl['cert'] : NULL,
	isset($ssl['ca']) ? $ssl['ca'] : NULL,
	isset($ssl['capath']) ? $ssl['capath'] : NULL,
	isset($ssl['cipher']) ? $ssl['cipher'] : NULL
	);
	}
	}

	if ($this->_mysqli->real_connect($hostname, $this->username, $this->password, $this->database, $port, $socket, $client_flags))
	{
	// Prior to version 5.7.3, MySQL silently downgrades to an unencrypted connection if SSL setup fails
	if (
	($client_flags & MYSQLI_CLIENT_SSL)
	&& version_compare($this->_mysqli->client_info, '5.7.3', '<=')
	&& empty($this->_mysqli->query("SHOW STATUS LIKE 'ssl_cipher'")->fetch_object()->Value)
	)
	{
	$this->_mysqli->close();
	$message = 'MySQLi was configured for an SSL connection, but got an unencrypted connection instead!';
	log_message('error', $message);
	return ($this->db_debug) ? $this->display_error($message, '', TRUE) : FALSE;
	}

	return $this->_mysqli;
	}

	return FALSE;
	}

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

	/**
	* Reconnect
	*
	* Keep / reestablish the db connection if no queries have been
	* sent for a length of time exceeding the server's idle timeout
	*
	* @return void
	*/
	public function reconnect()
	{
	if ($this->conn_id !== FALSE && $this->conn_id->ping() === FALSE)
	{
	$this->conn_id = FALSE;
	}
	}

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

	/**
	* Select the database
	*
	* @param string $database
	* @return bool
	*/
	public function db_select($database = '')
	{
	if ($database === '')
	{
	$database = $this->database;
	}

	if ($this->conn_id->select_db($database))
	{
	$this->database = $database;
	$this->data_cache = array();
	return TRUE;
	}

	return FALSE;
	}

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

	/**
	* Set client character set
	*
	* @param string $charset
	* @return bool
	*/
	protected function _db_set_charset($charset)
	{
	return $this->conn_id->set_charset($charset);
	}

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

	/**
	* Database version number
	*
	* @return string
	*/
	public function version()
	{
	if (isset($this->data_cache['version']))
	{
	return $this->data_cache['version'];
	}

	return $this->data_cache['version'] = $this->conn_id->server_info;
	}

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

	/**
	* Execute the query
	*
	* @param string $sql an SQL query
	* @return mixed
	*/
	protected function _execute($sql)
	{
	return $this->conn_id->query($this->_prep_query($sql));
	}

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

	/**
	* Prep the query
	*
	* If needed, each database adapter can prep the query string
	*
	* @param string $sql an SQL query
	* @return string
	*/
	protected function _prep_query($sql)
	{
	// mysqli_affected_rows() returns 0 for "DELETE FROM TABLE" queries. This hack
	// modifies the query so that it a proper number of affected rows is returned.
	if ($this->delete_hack === TRUE && preg_match('/^\sDELETE\s+FROM\s+(\S+)\s$/i', $sql))
	{
	return trim($sql).' WHERE 1=1';
	}

	return $sql;
	}

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

	/**
	* Begin Transaction
	*
	* @return bool
	*/
	protected function _trans_begin()
	{
	$this->conn_id->autocommit(FALSE);
	return is_php('5.5')
	? $this->conn_id->begin_transaction()
	: $this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
	}

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

	/**
	* Commit Transaction
	*
	* @return bool
	*/
	protected function _trans_commit()
	{
	if ($this->conn_id->commit())
	{
	$this->conn_id->autocommit(TRUE);
	return TRUE;
	}

	return FALSE;
	}

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

	/**
	* Rollback Transaction
	*
	* @return bool
	*/
	protected function _trans_rollback()
	{
	if ($this->conn_id->rollback())
	{
	$this->conn_id->autocommit(TRUE);
	return TRUE;
	}

	return FALSE;
	}

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

	/**
	* Platform-dependent string escape
	*
	* @param string
	* @return string
	*/
	protected function _escape_str($str)
	{
	return $this->conn_id->real_escape_string($str);
	}

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

	/**
	* Affected Rows
	*
	* @return int
	*/
	public function affected_rows()
	{
	return $this->conn_id->affected_rows;
	}

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

	/**
	* Insert ID
	*
	* @return int
	*/
	public function insert_id()
	{
	return $this->conn_id->insert_id;
	}

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

	/**
	* List table query
	*
	* Generates a platform-specific query string so that the table names can be fetched
	*
	* @param bool $prefix_limit
	* @return string
	*/
	protected function _list_tables($prefix_limit = FALSE)
	{
	$sql = 'SHOW TABLES FROM '.$this->escape_identifiers($this->database);

	if ($prefix_limit !== FALSE && $this->dbprefix !== '')
	{
	return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
	}

	return $sql;
	}

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

	/**
	* Show column query
	*
	* Generates a platform-specific query string so that the column names can be fetched
	*
	* @param string $table
	* @return string
	*/
	protected function _list_columns($table = '')
	{
	return 'SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE);
	}

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

	/**
	* Returns an object with field data
	*
	* @param string $table
	* @return array
	*/
	public function field_data($table)
	{
	if (($query = $this->query('SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE))) === FALSE)
	{
	return FALSE;
	}
	$query = $query->result_object();

	$retval = array();
	for ($i = 0, $c = count($query); $i < $c; $i++)
	{
	$retval[$i] = new stdClass();
	$retval[$i]->name = $query[$i]->Field;

	sscanf($query[$i]->Type, '%[a-z](%d)',
	$retval[$i]->type,
	$retval[$i]->max_length
	);

	$retval[$i]->default = $query[$i]->Default;
	$retval[$i]->primary_key = (int) ($query[$i]->Key === 'PRI');
	}

	return $retval;
	}

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

	/**
	* Error
	*
	* Returns an array containing code and message of the last
	* database error that has occurred.
	*
	* @return array
	*/
	public function error()
	{
	if ( ! empty($this->_mysqli->connect_errno))
	{
	return array(
	'code' => $this->_mysqli->connect_errno,
	'message' => $this->_mysqli->connect_error
	);
	}

	return array('code' => $this->conn_id->errno, 'message' => $this->conn_id->error);
	}

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

	/**
	* FROM tables
	*
	* Groups tables in FROM clauses if needed, so there is no confusion
	* about operator precedence.
	*
	* @return string
	*/
	protected function _from_tables()
	{
	if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
	{
	return '('.implode(', ', $this->qb_from).')';
	}

	return implode(', ', $this->qb_from);
	}

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

	/**
	* Close DB Connection
	*
	* @return void
	*/
	protected function _close()
	{
	$this->conn_id->close();
	}

	}