I'm creating a simple Mail-like app, just to practice CoreData and Bindings. Here is an overview: 1.The data model It's quite simple, the picture speaks by itself: 2.The interface Now, what I've already done: 1.Created 2 NSArrayController's 'Mailboxes' and 'Emails'. 2.Bind their contexts Both are bind to AppDelegate managedObjectContext 3.Bind mailboxes table column to Mailboxes (array controller) arrangedObjects.name Now the question: How to bind the other table view's columns? Binding to the Emails array controller does not make much sense to me, since I have to bind to the selection of the mailboxes table somehow. Any tips are really appreciated! Thanks in advance.