CoreData issue: -[NSManagedObject setValue:]: unrecognized selector sent to instance

Question

I just started with CoreData yesterday, and I\'m going crazy :( I created a project that uses CoreData (ticked the box -use CoreData). Created the entities, and then created the

Answer 1

I found that by having relations to entities I had to make sure some of my relations would be to-many, I took a screenshot so you can see what I mean, a to-many relation is indicated by the double ended arrow