MySQLi isn’t a database: http://www.php.net/manual/en/intro.mysqli.php
What is PHP’s mysqli Extension?
The mysqli extension, or as it is sometimes known, the MySQL improved extension, was developed to take advantage of new features found in MySQL systems versions 4.1.3 and newer. The mysqli extension is included with PHP versions 5 and later.
The mysqli extension has a number of benefits, the key enhancements over the mysql extension being:
Object-oriented interface
Support for Prepared Statements
Support for Multiple Statements
Support for Transactions
Enhanced debugging capabilities
Embedded server support
CI uses a database abstraction layer, so if you want to use mysqli functionality - and I don’t know how it could be of any help, or harm for that matter - in config/database.php:
$db[‘default’][‘dbdriver’] = “mysql”;
becomes
$db[‘default’][‘dbdriver’] = “mysqli”;
...and that’s it, as far as I can tell. CI comes with an adapter/driver for mysqli, its just PHP5 only and less commonly used.
From the mysqli_driver.php:
**
* MySQLi Database Adapter Class - MySQLi only works with PHP 5
*
* Note: _DB is an extender class that the app controller
* creates dynamically based on whether the active record
* class is being used or not.
*
* @package CodeIgniter
* @subpackage Drivers
* @category Database
* @author ExpressionEngine Dev Team
* @link http://ellislab.com/codeigniter/user-guide/database/
*/
class CI_DB_mysqli_driver extends CI_DB {
var $dbdriver = 'mysqli';
