ADO.NET Entity Framework provides an Object Relational Mapping (ORM) service, mapping the relational database schema to objects. The ADO.NET Entity Framework defines several layers, these can be summarized as:
Logical - this layer defines the relational data and is defined by the Store Schema Definition Language (SSDL).
Conceptual - this layer defines the .NET classes and is defined by the Conceptual Schema Definition Language (CSDL)
Mapping - this layer defines the mapping from .NET classes to relational tables and associations, and is defined by Mapping Specification Language (MSL).
Connector/Net integrates with Visual Studio to provide a range of helpful tools to assist development.
A full treatment of ADO.NET Entity Framework is beyond the scope of this manual. If you are unfamiliar with ADO.NET, review the Microsoft ADO.NET Entity Framework documentation.
Tutorials on getting started with ADO.NET Entity Framework are available. See Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source and Tutorial: Databinding in ASP.NET Using LINQ on Entities.