将NSManagedObject更新为核心数据

Question

So I have a tabbed application. The first tab allows a user to enter information in ~20 fields that describe a NSManagedObject. They are then able to save this into core data, and that works just fine.

The second tab is a TableView of all of the existing submissions. Now when a user clicks on a cell in the TableView, it will open up the first tab and repopulate all of the fields that were originally saved into core data. When the user clicks save again, I want the existing submission in core data to be updated, instead of a new insertion into core data.

I have found a lot of information saying that I should make a fetch request and then update it like that. But that seems redundant to me because I already have the object that was saved passed to the first tab/ViewController.

If you could point me to some code that would help my situation or describe a way you might accomplish this scenario, I would greatly appreciate it!

Answer 1

Since you have a reference to the NSManagedObject in the first tab, you can update its properties to the new values when the user saves. You can then save the changes to your NSManagedObject (let's call it myObject for simplicity) by calling [[myObject managedObjectContext] save:&error] where error is an NSError * .