I think that's where the majority of ORM criticism comes from ... namely the idea (that some may hold) that you don't need to have a good mental model of SQL if

I think that's where the majority of ORM criticism comes from ... namely the idea (that some may hold) that you don't need to have a good mental model of SQL if you just use ORMs. I can see some people who are intimidated by SQL use ORM as a crutch to work with relational databases. OOP and SQL are different paradigms. An OOP abstraction over SQL is never going to be perfect so to properly and responsibly use an ORM framework you have to understand what's going on under the hood. If you don't, then yes, you will create a mess for anything other than the most trivial use-cases.