Uimanaged Document with CoreData
I use UIManaged Document with coreData 

first: i successfully adding object to specific Entity  and fetching all objects in this Entity then use the objectID returned from this fetch to get the object next time but nothing returned 

using both Methode [ManagedObjectcontext ObjectwithId: object.objectID];

and existingObjectWithID 
but thier is no object returned from those methods 
it returned nil 
Uimanaged Document with CoreData
===

I use UIManaged Document with coreData 

first: i successfully adding object to specific Entity  and fetching all objects in this Entity then use the objectID returned from this fetch to get the object next time but nothing returned 

using both Methode [ManagedObjectcontext ObjectwithId: object.objectID];

and existingObjectWithID 
but thier is no object returned from those methods 
it returned nil 