MySQLi is an extension for PHP, often referred to as MySQL improved. It was introduced in PHP 5.0, and will be in every version following (until something better comes along). It allows you to use all of the MySQL database (version 4.1.3 or newer) servers features. Some features of MySQLi.
It’s object oriented interface, making it easier to use
Helping secure you code
You to run more than one query at a time
<?php mysqli_connect('localhost','username','password','database'); ?>