1.The main set of classes for data access are part of the ADO.NET and are contained in
System.Data
namespace.
2.Entity Framework extends the ADO.NET with more functionalists and also wizards in Visual Studio.
Namesapces:
System.Data.Objects,
System.Data.EntityClient
.
Here is a link:
http://msdn.microsoft.com/en-us/data/ee712907[
^]
3.LINQ could be used on top of both, and its main namespace is
System.Linq
.