Framework (EF) allows you to program against a model instead of dealing
with a database directly. In EF 4.0 (that ships with .NET 4.0) you
typically design a model from an existing database visually, using a
designer provided for that purpose. EF 4.1 builds on top of what EF 4.0
provided and allows you to create models directly at code level. That
means instead of creating any database and then using a designer to
define models, you create plain .NET classes and then use EF 4.1
techniques to make them EF models. This approach is referred as Code
First because you focus on the source code of the model classes first.
Once the models are ready Code First can also generate database tables
out of those model classes. In this tutorial you will learn the basics
of developing an application using Entity Framework Code First.