Book Image

Mastering Entity Framework

By : Rahul Rajat Singh
Book Image

Mastering Entity Framework

By: Rahul Rajat Singh

Overview of this book

<p>Data access is an integral part of any software application. Entity Framework provides a model-based system that makes data access effortless for developers by freeing you from writing similar data access code for all of your domain models.</p> <p>Mastering Entity Framework provides you with a range of options when developing a data-oriented application. You’ll get started by managing the database relationships as Entity relationships and perform domain modeling using Entity Framework. You will then explore how you can reuse data access layer code such as stored procedures and table-valued functions, and perform various typical activities such as validations and error handling. You’ll learn how to retrieve data by querying the Entity Data Model and understand how to use LINQ to Entities and Entity SQL to query the Entity Data Model.</p>
Table of Contents (19 chapters)
Mastering Entity Framework
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Modeling a one-to-many relationship


Now, let's start our discussion by looking at the models that have one-to-many relationships. If we look at the Employer and Employee relation, we can see that the Entity Frameworks Entity Data Model generator was able to figure out the one-to-many relationship between the database tables and was able to create the same relationship in the conceptual Entity Data Model as well.

A one-to-many relationship between entities

Also, the relationship in the Entity Data Model is represented by 1 with the entity at the one end of the relationship and by * with the entity on the many end of the relationship.

If we look at our Entity Data Model, we can see that the Entity Framework created Navigation Properties in the entities. The entity at the one end of the relationship will have a navigation property of the collection type to hold multiple entities on the many end. Similarly, the Entity on the many end of the relation will have a navigation property that will let...