Core Data simple relationship - NSSet

Question

I am trying to play with relationships in xCode and I'm having some problems:

I want to create a simple User to favoriteThing relationship. I created a model, so every user looks like this:

extension User {

@NSManaged var name: String?
@NSManaged var favoriteThings: NSSet?

}

extension FavoriteThing {

@NSManaged var thingName: String?
@NSManaged var user: User?

}

And I got a tableview conected (so it displays favoriteThing for each user).

The thing is, when I create a new favoriteThing how to add this thing to favoriteThings NSSet that is created in User class?

And what about when I delete this favoriteThing from my table view? (it is managed by fetchedResultsController) How to delete it also from mentioned favoriteThings NSSet?

Any help appreciated!

Answer 1

In the case of a one-to-many relationship, the easiest way to add an object to the to-many relationship is to set the property of the inverse to-one relationship:

theFavoriteThing.user = theUser

This automatically updates theUser.favoriteThings to include theFavoriteThing .

And to remove it just set the inverse to-one relationship to nil :

theFavoriteThing.user = nil