Quote Originally Posted by geotnt View Post
Correct me if I'm wrong, but isn't a "database" a collection of inter-related files making up the records describing the products?
No, not really. At least not in this context.
A MySQL database is NOT a casual self-managed simple low-end "database" like MS Access or some flat-text-file with which you might be more familiar. This is far more efficient and secure than those other approaches.
Quote Originally Posted by geotnt View Post
It would then stand to reason that these files are kept somewhere.
On a strictly technical sense, yes there are "files" which store the data, but those files are managed entirely by the MySQL database engine running on your server, and those files are NOT accessible to you yourself, nor to Zen Cart.
Quote Originally Posted by geotnt View Post
All I'm asking is where does Zen Cart keep them?
Again, Zen Cart has NO control over those physical "files".
Instead, Zen Cart simply logs into the database engine which takes care of looking up and supplying any requested data and updating/inserting any data as directed by you while using the Zen Cart application.