Book Image

Entity Framework Tutorial

By : Joydip Kanjilal
Book Image

Entity Framework Tutorial

By: Joydip Kanjilal

Overview of this book

<p>The ADO.NET Entity Framework is a new way to build the data access layer of your Windows or web applications. It's an Object Relational Mapping (ORM) technology that makes it easy to tie together the data in your database with the objects in your applications, by abstracting the object model of an application from its relational or logical model.<br /><br />This clear and concise book gets you started with the Entity Framework and carefully gives you the skills to speed up your application development by constructing a better data access layer. It shows you how to get the most from the ADO.NET Entity Framework to perform CRUD operations with complex data in your applications.<br /><br />This tutorial starts out with the basics of the Entity Framework, showing plenty of examples to get you started using it in your own code. You will learn how to create an Entity Data Model, and then take this further with Entity types. You will also learn about the Entity Client data provider, learn how to create statements in Entity SQL, and get to grips with ADO.NET Data Services, also known as Project Astoria.</p>
Table of Contents (13 chapters)
Entity Framework Tutorial
Credits
About the Author
About the Reviewer
Preface

What are Object Services?


Object Services enable you to work with entities such as memory objects. It strives to eliminate the impedance mismatch that exists between the relational or logical and the programming models. You can use Object Services for change tracking, data binding objects to data controls, and handling concurrency conflicts. Object Services support both LINQ and Entity SQL queries. The classes of the Object Services Layer is contained is the System.Data.Objects and System.Data.Objects.DataClasses namespaces. The ObjectContext is the core of the Object Services Layer.

The ObjectContext class encapsulates the following:

  • An EntityConnection instance

  • A MetadataWorkspace instance

  • An instance of ObjectStateManager

While the EntityConnection instance is responsible for connecting to the database, the instance of MetadataWorkspace contains the metadata information that describes the entity data model. The ObjectContext class also encapsulates an ObjectStateManager instance that enables...