Book Image

WCF 4.0 Multi-tier Services Development with LINQ to Entities

By : Mike Liu
Book Image

WCF 4.0 Multi-tier Services Development with LINQ to Entities

By: Mike Liu

Overview of this book

WCF is the Microsoft model for building services, whereas LINQ to Entities is the Microsoft ORM for accessing underlying data storage. Want to learn both? You would normally have to dig through huge reference tomes—so wouldn't you agree that a simple-to-follow practical tutorial on WCF and LINQ to Entities is the way to get ahead?This book is the quickest and easiest way to learn WCF and LINQ to Entities in Visual Studio 2010. WCF and LINQ to Entities are both powerful yet complex technologies from Microsoft—but you will be surprised at how easily this book will get you get up and running with them.Mastery of these two topics will quickly enable you to create Service-Oriented applications, and allow you to take your first steps into the world of Service Oriented Architecture without becoming overwhelmed.Through this book, you will learn what's going on behind the scenes with WCF, and dive into the basic yet most useful techniques for LINQ to Entities. You will develop three real-world multi-tiered WCF services from beginning to end, with LINQ to Entities being used in the data access layer of the services. Various clients including windows console applications, the WCF Test Client, Windows Form applications and WPF applications will be created to test these WCF services. By the end of this book, you will be 100% confident that you know WCF and LINQ to Entities, not only in theory, but with sound real-world experience.
Table of Contents (16 chapters)
WCF 4.0 Multi-tier Services Development with LINQ to Entities
Credits
About the Author
About the Reviewers
Preface
Index

Comparing LINQ to Entities with LINQ to Objects


In the previous chapter, we used LINQ to query in-memory objects. Before we dive further into the world of LINQ to Entities we first need to look at the relationships between LINQ to Entities and LINQ to Objects.

Some key differences between LINQ to Entities and LINQ to Objects are:

  • LINQ to Entities needs an Object Context object. The ObjectContext object is the bridge between LINQ and the database (we will explain more about ObjectContext later). LINQ to Objects doesn't need any intermediate LINQ provider or API.

  • LINQ to Entities returns data of type, IQueryable<T>, whereas LINQ to Objects returns data of type, IEnumerable<T>.

  • LINQ to Entities queries are translated to SQL by way of Expression Trees, which allow them to be evaluated as a single unit and translated to appropriate and optimal SQL Statements. LINQ to Objects queries do not need to be translated.

  • LINQ to Entities queries are translated to SQL calls and executed on the...