Managed Object ID

• Get the string URL representation from a ManagedObjectID

1 2	NSURL *urlID = [objectID URIRepresentation]; NSString *strUrlID = [urlID absoluteString];

• Get the ManagedObjectID from a URL string

1 2	NSURL *urlID = [[NSURL alloc] initWithString:strUrlID]; NSManagedObjectID *objectID = [[managedObjectContext persistentStoreCoordinator] managedObjectIDForURIRepresentation:urlID];

• Get the ManagedObject by a ManagedObjectID

1 2	NSError *error = nil; NSManagedObject *managedObject = [moc existingObjectWithID:objectID error:&error];

• Check if a ManagedObject is new

1	BOOL isNew = managedObject.objectID.isTemporaryID;

• Get the permanent object IDs for the objects in a child context.

1 2 3 4 5 6 7 8

NSError *error = nil; [childManagedObjectContext obtainPermanentIDsForObjects:childManagedObjectContext.insertedObjects.allObjects error:&error]); // . . . Check for an error . . . [childManagedObjectContext save:&error]; // . . . Check for an error . . .

Refs
http://stackoverflow.com/questions/3519334/how-to-uniquely-identify-nsmangedobject-with-string
http://stackoverflow.com/questions/10811280/how-to-get-the-objectid-from-url
http://stackoverflow.com/questions/3013288/how-to-use-managedobjectid-the-right-way
http://iphonedevelopment.blogspot.com.au/2009/07/core-data-determining-if-managed-object.html
http://stackoverflow.com/questions/11990279/core-data-do-child-contexts-ever-get-permanent-objectids-for-newly-inserted-obj/11996957#11996957