Professional iPhone® and iPad™ Database Application Programming

Chapter 8. Core Data–Related Cocoa Features

WHAT'S IN THIS CHAPTER?

• Setting and getting data using key-value coding

• Implementing a loosely coupled application architecture with messaging and key-value observing

• Creating predicates in several ways and using them to filter data

• Building sort descriptors to order your data structures

In the last three chapters, you learned about the fundamentals of the Core Data architecture — how to model your data and how to build a complete data-centric application using the Core Data framework. This chapter provides a more detailed look at some of the Cocoa functionality that you used with Core Data. In addition to their application in Core Data, you can use these features in other interesting ways.

In this chapter, you learn more about some important Cocoa technologies: key-value coding, key-value observing, predicates, and sort descriptors.

While you have seen these features used with Core Data, they are an integral part of the Cocoa framework. You can use these concepts and their associated classes in ways that reach far beyond Core Data. For example, you can use predicates and the NSPredicate class to filter and query regular Cocoa data structures such as arrays and dictionaries. You can develop loosely coupled, message-based application architectures using the concepts of key-value coding and key-value observing. Adding a deeper knowledge of these Cocoa features will broaden your knowledge of the development platform and provide you with more tools ...