In which situations does a managed object context have changes?

Question

In which situations does a managed object context have changes?

What can happen that -hasChanges returns YES?

Answer 1

There are several possibilities: you inserted a new entity, you deleted an entity, you modified an entity(either an attribute or a relation).

Answer 2

You can find out by observing NSManagedObjectContextObjectsDidChangeNotification notifications

NSManagedObjectContext notifications