iOS 7 Programming Cookbook

18.0. Introduction

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.

With the new LLVM compiler, all you have to do in order to include Core Data into your project is to include the umbrella header file, like so:

#import "AppDelegate.h"
#import <CoreData/CoreData.h>

@implementation AppDelegate

<# Rest of your code goes here #>

To be able to work with Core Data, you need to understand that a Core Data stack is based on the following concepts:

Persistent store

The object that represents the actual data base on disk. We never use this object directly.

Persistent store coordinator

The object ...