First of all, you can't do ORM without knowing SQL it's an inherently leaky abstraction and that's not changing anytime soon.

Using SQL is great except what do you define as 'SQL'. Is it MySQL, Oracle or Postgres? How do I migrate between them? Forget data migration, I'm just talking about the data model and constraints. Today I run my app on MySQL but tomorrow the environment will demand Oracle.

I have an app that can run on any database that Hibernate supports with zero code changes and 1 line in a config file including my data constraints.