[jqpabc123]

I have done this for simple web apps in the past.

And I have had programmers who used the resulting apps call me a liar and tell me it's not possible.

The file system is itself a multi-user indexed data store built right into the OS kernel. However, it obviously is not a relational DBMS.

So if your needs are limited and can be satisfied by a simple indexed data store, this can work remarkably well.

Even though some "software engineers" will tell you it can't because they have been trained differently.