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

Change Tracking and Identity Resolution Using ObjectContext


Change Tracking in the Entity Framework is a feature that enables you detect and resolve conflicts that arise out of concurrent data updates on a particular entity. Such scenarios are commonly known as concurrency conflicts.

Two ways to handle data concurrencies in a multi-user environment are:

  • Optimistic

  • Pessimistic

In the Optimistic mode, the record is read but not locked. You need to check whether a record to be saved has already been modified. In essence, you need to track the changes in the data before you do any changes.

In the Pessimistic mode, the record being modified is locked from other users until the lock on the record is released. Therefore, Pessimistic concurrency is not a good choice, especially when you have a large number of users accessing the application at the same point in time.

By default, the Entity Framework follows the Optimistic concurrency model. When the Object Services layer saves the changes in an object...