Core Data fetching... Why doesn't Managed Object get fetched using context B after inserting it in context A and saving context A?

Question

I am not sure what I'm missing here so I'll try to explain a problem I'm having.

I have two nsmanagedobjectcontexts. I will call them A and B.

1. I insert a new entity E in A
2. I save A
3. from B I try to fetch all the E entities found in store with a simple fetchRequest
4. When executing the NSFetchRequest to get all E entities from B I cannot get the one I inserted in A even though A was saved.
5. I can get E if I execute the NSFetchRequest against A.

I thought that once I save a context the ManagedObject in that context would get saved to the persistent store (I only have one persistent store setup). So then I thought that I could get the managed object E from what ever context I wanted since any NSFetchedRequest fetches from the persistent store into the context I'm executing it on.

What am I missing here? Why can't I get E from any context I want after saving context A in which E was inserted in in the first place?

Answer 1

You need to merge the changes from context A in to context B. or instantiate context B after the save of context A.

Take a look at the documentation for mergeChangesFromContextDidSaveNotification on NSManagedObjectContext.