[macspoofing]

ORMs pretend to give you full abstraction, but in reality you have to be aware of the underlying SQL layer when you build your object model.

[antihero]

I find that if you are aware of the SQL underneath, they are good for saving time.

Do you really want to write SQL to retrieve data and code to populate an object for every damn thing in your system?

[macspoofing]

I agree. Problems happen if you treat ORMs as a total blackbox.