loaded by a single application and used by our customers with MS Access,
From by previous job where we had an Access based backoffice application, you might want to learn enough to be ready to switch to something better (ie postgres) when you feel the need. Access is a booby trap setup by Microsoft to sell SQL server. It will work well up to a certain point, then die miserably (some of our web pages were taking minutes to load !). When this happens many people complain and you usually buy SQL server to ease the pain.
Or, as we did, you ditch the MS stuff and switch to other tools. I wasn't in charge of this, so can't say more, but beware of Access.
