在demo.phpmyadmin.net上远程连接数据库？

Question

I teach a little php and SQL and I would like my students to temporarily connect to a database they have testet on demo.phpmyadmin.net, is this done simply by using:

  $username = "root";
  $password = "";
  $hostname = "192.168.30.23";

If so it doesn't seem to work for me. :)