The OP mentioned check constraints: what I would be looking for as a bare minimum, and which I'd imagine is low-hanging fruit, is being able to put a function on the server (as I often have numerous clients in numerous languages, and thereby want my "last stand" on data integrity to be a single piece of code written in one language as close to the data as possible) that verified the data before letting me write it; it then does not matter if the data being stored only has four data types: I can have my verifier at least check that I am storing an array with four numbers that are all integers between 0 and 255, even if I can't express "a color".