<?php
define('HOST', 'localhost');
define('USER', 'mydbuser');
define('PASS', 'mydbpass');
define('DBNAME', 'mydb');
$link = mysql_connect(HOST, USER, PASS);
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db(DBNAME, $link);
?>
hxxp://php.net/manual/en/mysqlinfo.api.choosing.php