Book Image

Core Data iOS Essentials

By : Bintu Harwani, B. M. Harwani
Book Image

Core Data iOS Essentials

By: Bintu Harwani, B. M. Harwani

Overview of this book

Core Data is the essential ingredient in data driven iOS apps. It's used for storing, retrieving, and manipulating application data in databases, XML, and binary formats. It's an essential component for iPhone, iPod Touch, and iPad apps.Core Data Essentials provides a clear, readable guide to the most useful aspects of Core Data. Built around a realistic example app, the book showcases the most important aspects of Core Data development in the context of a complete, functioning app written in Objective C.The book starts with a tour of how the app works. Then you'll see how to easily display data using the Table View. You'll learn how to develop an appropriate data model that fits the needs of your app, then implement that model as updatable data objects. You'll see how to update data and build relationships between objects and learn how Core Data can work with search, and how to provide your users with friendly data editing features.
Table of Contents (19 chapters)
Core Data iOS Essentials
About the Author
About the Reviewers

Using Predicate Builder for creating a search criterion

Xcode provides a visual tool: Predicate Builder that helps in creating predicates (queries for extracting rows from entities) for us. Let us try using the Predicate builder to display all customer names that contain characters 'Ca'.

So, let us open our Data Model by double-clicking the prob.xcdatamodel file in the Resources group in the Xcode Project window. Xcode's data modeling tool will open and we find our Customer entity in it. From the Property pane, select the + (plus) button, a menu with several options such as: Add Attribute, Add Fetched Property, Add Relationship, and Add Fetch Request will popup. Out of these four options, Add Fetched Property and Add Fetch Request can be used for building predicates. Let us see them one by one.

Fetched properties

A fetched property is a type of attribute that associates a managed object with other managed objects based on the specified condition. That is, the predicate to define the objects...