I have records that are added, updated. Then sync them with server. According to server response, if one of them fail to update, I would like to have that NSManagedObject to previous value. As I research, UndoManager works as stack, so I can't find any record with Id and undo that record, am I right?
And finally, what would you suggest for this issue?
You could track your objects by introducing your own ID attribute and syncing that with the server. I think this is a solid and robust design - I have used it many times without problems.
Apple does provide an objectID with each managed object, but this is really meant to ensure consistency of data across different managed object contexts. I would not recommend "abusing" this ID for external systems.
Your server could provide the old values (along with the message that it was not updated) and you could write that back into your Core Data store, finding the record using your ID attribute. For more granular change and update management, you could even use a time stamp attribute.
