If I'm not mistaken (chances are that I am...) he wants something like:
PHP Code:
<?php
// Script running on www.myclientsite.com
// Set up db connection to remote server
include('http://www.remoteserver.com/db_conn.php');
// Now we can use the $db object
$db->query(...);
If you're trying to implement something like that, there's no way you can hide the connection details.