ADO.NET Entity Framework Tutorial and Basics
Last Update: 06 June, 2010

" ADO.NET Entity Framework is an object-relational mapping (ORM) framework for the .NET Framework.

ADO.NET Entity Framework abstracts the relational (logical) schema of the data that is stored in a database and presents its conceptual schema to the application. For example, in the database, entries about a customer and their information can be stored in the Customers table, their orders in the Orders table and their contact information in yet another Contacts table. For an application to deal with this database, it has to know which information is in which table, i.e., the relational schema of the data is hardcoded into the application.

The disadvantage of this approach is that if this schema is changed the application is not shielded from the change. Also, the application has to perform SQL joins to traverse the relationships of the data elements in order to find related data.

A primary goal of the of ADO.NET is to raise the level of abstraction for data programming, thus helping to eliminate the impedance mismatch between data models and between languages that application developers would otherwise have to deal with. Two innovations that make this move possible are Language-Integrated Query and the ADO.NET Entity Framework. The Entity Framework exists as a new part of the ADO.NET family of technologies. ADO.NET will LINQ-enable many data access components: LINQ to SQL, LINQ to DataSet and LINQ to Entities. " - (Collected).

2 Basic Tutorials of Entity Framework can be found here:
Evolving ADO.NET Entity Framework in .NET 4 and Beyond
ADO.NET Entity Framework Tutorial and Basics