Working with WCF Data Services and Entity Framework
In this section, we will discuss how we can create a WCF Data Service using Entity Framework and the AdventureWorks database. To add a WCF Data Service application to an existing web application, follow these steps:
Create an ASP.NET application:

Create a new Entity Data Model and name it
AdventureWorks:
Select Code First from database:

In the Entity Data Model Wizard dialog, specify the data connection properties and click Next:

Next, choose the database objects you want to be part of the Entity Data Model:

Now, right-click on the project in the solution explorer window and select Add New Item.
Select WCF Data Service from the list of the templates displayed, specify a name, and click OK.

And, you are done! At first glance, the WCF Data Service class looks like this:
using System.Data.Services;
using System.Data.Services.Common;
namespace WCFDataServices
{
public class CurrencyDataService : DataService< /* TODO: put
your data source...