I can, sadly, one up you on that:

The same table stores: Addresses (primary, secondary), sex, names (up to 3), date of birth, what currency, and many MANY more values.

Yes, that's one table.

Also: Another table literally stores full tables in it. (Basically some kinda key with which to identify the subtable so you can select on it.)

Progress has no real concept of set based queries, instead it accesses all tables like a cursor.

And that's not even scratching the surface. The DB is bad and should feel bad. Just yesterday I went into a 2 hr rant about it with some people I often talk to.

Foreign keys, too, are a foreign concept to progress. But hey, work is work.