A type system like what a programming languages have doesn't make sense for databases. For inserts, sure (but then, it's straightforward to use the host langua

A type system like what a programming languages have doesn't make sense for databases. For inserts, sure (but then, it's straightforward to use the host language for that). But once you move beyond simple cases, data changes over time, not atomically. It's also common for data to be distributed. Static type system can handle either of these things. If your database can't go down for the duration of a migration (which will need more time now, to type-check all the data), and you don't have a way to ensure all clients are updated at the same time also, then you can't use static type checking like programming languages have.