Book Image

Entity Framework Core Cookbook - Second Edition

By : Ricardo Peres
Book Image

Entity Framework Core Cookbook - Second Edition

By: Ricardo Peres

Overview of this book

Entity Framework is a highly recommended Object Relation Mapping tool used to build complex systems. In order to survive in this growing market, the knowledge of a framework that helps provide easy access to databases, that is, Entity Framework has become a necessity. This book will provide .NET developers with this knowledge and guide them through working efficiently with data using Entity Framework Core. You will start off by learning how to efficiently use Entity Framework in practical situations. You will gain a deep understanding of mapping properties and find out how to handle validation in Entity Framework. The book will then explain how to work with transactions and stored procedures along with improving Entity Framework using query libraries. Moving on, you will learn to improve complex query scenarios and implement transaction and concurrency control. You will then be taught to improve and develop Entity Framework in complex business scenarios. With the concluding chapter on performance and scalability, this book will get you ready to use Entity Framework proficiently.
Table of Contents (15 chapters)
Entity Framework Core Cookbook - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Creating one-to-many maps


When an entity can be associated with one or more entities of another type, and each of these entities is associated with at most one entity of the first type, we call that one-to-many. It is one of the more basic kinds of relation, and, if looked at from the other endpoint, it becomes a many-to-one relation. Some examples of this include the following:

  • A blog and its posts

  • A parent and their children

  • A folder and its sub-folders

  • An order and its details (items included)

You may notice that there is one difference: in some of these relations, the many side cannot exist without the one—for example, a child without a parent–while in others, it can—there can be a folder without a parent folder.

This is easy to represent in the domain model; the one side holds a collection of entities of the many side, and the many side holds a reference to an entity on the one side. Pretty simple.

Getting ready

We will be using the NuGet Package Manager to install the Entity Framework Core...