Currently there are multiple ways to perform validations before mutations:

1. add check constraints on postgres explicitly
2. create postgres triggers
3. remote-schemas

Many use-cases can be solved using 1 and 2 but its not easy to use them currently.

We can solve the problem of 1) more efficiently: In the data tab, we should be able to "select" check constraints during table create/modify. We can keep this similar to permissions UI but underneath it will translate to a simple "ADD CONSTRAINT" query.