In addition to supporting a designer-based development workflow, EF4 also enables a more code-centric option which we call “code first development”.  Code-First Development enables a pretty sweet development workflow.  It enables you to:

Develop without ever having to open a designer or define an XML mapping file

Define your model objects by simply writing “plain old classes” with no base classes required

Use a “convention over configuration” approach that enables database persistence without explicitly configuring anything

Optionally override the convention-based persistence and use a fluent code API to fully customize the persistence mapping

EF’s “code first development” support is currently enabled with a separate download that runs on top of the core EF built-into .NET 4.  CTP4 of this “code-first” library shipped this week and can be downloaded here. 

It works with VS 2010, and you can use it with any .NET 4 project (including both ASP.NET Web Forms and ASP.NET MVC).