Core Data is a powerful framework on the iOS SDK that allows programmers to store and manage data in an object-oriented way. Traditionally, programmers had to store their data on disk using the archiving capabilities of Objective-C, or write their data to files and manage them manually. With the introduction of Core Data, programmers can simply interact with its object-oriented interface to manage their data efficiently. In this chapter, you will learn how to use Core Data to create the model of your application (in the Model-View-Controller software architecture).
Core Data interacts with a persistent store at a lower level that is not visible to the programmer. iOS decides how the low-level data management is implemented. All the programmer must know is the high-level API she is provided with. But understanding the structure of Core Data and how it works internally is very important. Let’s create a Core Data application to understand this a bit better.
Core Data in an iOS application needs a bit of setting up. Fortunately, with Xcode, this process is very easy. You can simply create a Core Data application and leave the rest up to Xcode.
Follow these instructions to create a project in Xcode that uses Core Data:
Open Xcode, if it’s not open already.
From the File menu, select New→New Project...
In the New Project dialog, make sure iOS is the main category on the left and Application is the subcategory under it. Then on the righthand side of the dialog, choose Empty ...