config problem php

<?php
$host="...."; // Host name
$username="...."; // Mysql username
$password="......."; // Mysql password
$db_name="...."; // Database name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");
?>


another php file:

<?php
include('config.php');
...
sql query
...
?>