So what exactly is Core Data used for, and what is it capable of? To be technical, it is an object graph and persistence framework. To be less technical, it is a framework that makes it easy to save, change, track, and sort lots of data.
In this section, we're going to cover the model aspect of Model-View-Controller (MVC) again, and look at how Core Data ties into those ideas of separating data from views. Then, we're going to look at how Core Data represents data relationships, and finally, we'll learn how we can create our own specific descriptions of the data our app needs to manage.
In the very first chapter of this book, we took some time discussing the concept of MVC, and how we separate an application's data from its interface, and connect it through the controller. We've come a long way since then, and we've learned a ton about creating views and programming controllers.
However, as it stands now, our ViewController class is completely owning the model...