Question

I see 3 variants:

1. specify db constraints in schema (*.sql) file
2. specify db constraints in ORM stuff(with xml/annotations/whatever)
3. use mix of 1) and 2)

Is there any Best Practice for this topic?
Particularly, I’m interested in Hibernate world.

Answer 1

The only constraints that are applied are the constraints that are in the database. Specifying constraints in Hibernate annotations is only useful if you’re using the hibernate tools to generate the database SQL schema from the Java source code. In the end, it always ends up being in the SQL.

So if you maintain the schema manually and don’t generate it from the Java annotations, using annotations to specify them is useless (except for documentation purposes).