I think it is very uncommon for any game to use an "open", unprotected SQL database.
Single player games, that are installed and run entirely on the client PC, typically won't use an SQL database, because that incurs too much "heavy weight".
I would recommend you to hire some very cheap webspace with LAMP stack (Linux, Webserver, PHP, MySQL). Then build a very simple website on top of that, using PHP forms to interact with the database.
In your course you can then use that system for demonstration purpose. That approach will give you a lot of flexibility, about what you can show or what exercises you can offer.
There are also bundles like XAMPP, which allow to install such a system on local PCs quite easily.