Comment by stephenlf

> The database can be dumb and fast because the application layer is smart and careful.

I’ve always baked important invariants directly into the database with constraints and triggers. Maybe this is because I work on internal apps, where the data is more important than the presentation. Maybe it’s from my functional programming experience and some need to make invalid states unrepresentable.

Regardless, I believe that the data layer should be the most carefully designed part of an app.