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:
=>Support for Prepared Statements
=>Support for Multiple Statements
=>Support for Transactions
=>Enhanced debugging capabilities
=>Embedded server support