[shadesandcolour]

"Model code" in that sentence refers purely to NSManagedObject subclasses. Create other model objects to work with your entities instead of asking them to do things for you. How much business logic belongs in the class that models a tweet?

[sivanmz]

> Create other model objects to work with your entities instead of asking them to do things for you.

Regardless of persistence, using such "manager" objects to operate on data records is procedural rather than object oriented programming.