Connect localhost with php

We use php language to connect sarver with MySql.

Code:

[php]

<?php
$con = mysql_connect("hostname","username","password");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
?>

[/php]

In apache sarver host name is "localhost", username is "root" and password is null ("") but in zend sarver host name is "localhost", username is "root" and password is "root123" what you have set.