The longer a database has existed, the more likely somebody in the company wrote something crucial that accesses it without your knowledge and without going thr

The longer a database has existed, the more likely somebody in the company wrote something crucial that accesses it without your knowledge and without going through your ORM (usually because your ORM isn't implemented for the language they're using, or it emits bad queries for their use case). Sanity checks that aren't enforced by the database can't be relied on to be up to date or even happen at all.