In this chapter, we learned a lot about Core Data. First we revisited the concept of the model within an MVC application, and learned about how entities, attributes, and relationships work in Core Data. We became acquainted with the Core Data model editor, and then used the editor to build up a real data model for our app. We also learned about the Core Data stack, which makes persistence work. Finally, we took all of this knowledge to implement saving, loading, and deleting permanent data in our app.
In the next chapter, we're going to take one more huge jump forward: learning how to use watchOS to create an Apple Watch companion app for your app. I could say more, but let's not spoil any of the fun.