WCF Data Services 4.5
WCF Data Services (formerly known as "ADO.NET Data Services") is a component of the .NET Framework that enables you to create services that use the Open Data Protocol (OData) to expose and consume data over the Web or intranet by using the semantics of representational state transfer (REST). OData exposes data as resources that are addressable by URIs. Data is accessed and changed by using standard HTTP verbs of GET, PUT, POST, and DELETE. OData uses the entity-relationship conventions of the Entity Data Model to expose resources as sets of entities that are related by associations.
WCF Data Services can expose data that originates from various sources as OData feeds. Visual Studio tools make it easier for you to create an OData-based service by using an ADO.NET Entity Framework data model. You can also create OData feeds based on common language runtime (CLR) classes and even late-bound or un-typed data.
WCF Data Services also includes a set of client libraries, one for general .NET Framework client applications and another specifically for Silverlight-based applications. These client libraries provide an object-based programming model when you access an OData feed from environments such as the .NET Framework and Silverlight.