Let’s take a closer look at the radiobuttons and how they relate to core data. Remember how the countries drawer pane looks in Interface Builder:

I want the four radiobuttons to correspond to the four possible “VAT regions” in the data model:

Maybe I need to explain what I mean by “VAT regions”, as most non-europeans will [...]

I’m back after finally getting the tax forms mailed in. What a waste of time that is. A civilized society shouldn’t be doing these things to their citizens.
Now the time has arrived to construct the CountriesController class. This class controls the model and view for the countries data element. It is instantiated by the AppController [...]

I realize I skipped a step right in the beginning. I’m sure I skipped more steps, but at least I noticed this one. The step I missed is:
How does one create a new window and its associated objects and have it created when a menu option is clicked or another part of the application needs [...]

I promised to describe how to implement validation to ensure uniqueness in the database. Here goes.
First, you need to open the datamodel in XCode. With the datamodel on screen, select File… New… and you’ll see “Managed Object Class” under the section “Design”. Note that this choice simply isn’t there unless you first opened the data [...]

My travails as I implement my first project in Cocoa, part I.