Book Image

Code-First Development with Entity Framework

By : Sergey Barskiy
Book Image

Code-First Development with Entity Framework

By: Sergey Barskiy

Overview of this book

<p>Entity Framework Code-First enables developers to read and write data in a relational database system using C# or VB.NET. It is Microsoft's answer to demand for an ORM from .NET developers.</p> <p>This book will help you acquire the necessary skills to program your applications using Entity Framework. You will start with database configuration and learn how to write classes that define the database structure. You will see how LINQ can be used with Entity Framework to give you access to stored data. You will then learn how to use Entity Framework to persist information in a Relational Database Management System. You will also see how you can benefit from writing ORM-based .NET code. Finally, you will learn how Entity Framework can help you to solve database deployment problems using migrations.</p>
Table of Contents (15 chapters)
Code-First Development with Entity Framework
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Updating a record


Let's take a look at how we can change the data after inserting it. This is done in the SQL world by issuing an UPDATE command. In the Entity Framework world, you do not need to perform this step. Instead, we just need to find an instance of an object in the collection, change its properties, and then call the familiar SaveChanges method. Now, we just need to get an object from the database to update. You just saw how to do this in the Querying data in a database section. Here is what the update code looks like:

using (var context = new Context())
{
    var savedPeople = context.People;
    if (savedPeople.Any())
    {
        var person = savedPeople.First();
        person.FirstName = "Johnny";
        person.LastName = "Benson";
        context.SaveChanges();
    }
}

As you can see, we simply point to the People property of the context. Then, we check to make sure that there is at least one entity in the collection using the Any() method, which is part of LINQ. Then, we...