[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class MyDataService : EntityFrameworkDataService<MyContext>
{
    public static void InitializeService(DataServiceConfiguration config)
    {
        config.SetEntitySetAccessRule("*", EntitySetRights.All);
        config.SetServiceOperationAccessRule("*", ServiceOperationRights.All);
        config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;

        config.UseVerboseErrors = true;
    }
}

public class MyContext : DbContext
{
    public DbSet<TableDelivery> TableDeliveries { get; private set; }

    public MyContext() :
        base(System.Web.Configuration.WebConfigurationManager.ConnectionStrings["ServiceConnectionString"].ConnectionString)
    {
        TableDeliveries = this.Set<TableDelivery>();

        Database.SetInitializer(new MyInitializer()); /* DropCreateDatabaseAlways */
        //Database.SetInitializer<MyContext>(null);

        this.Configuration.ProxyCreationEnabled = false;
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new TableDeliveryConfiguration());
    }
}

[ServiceContract]
public interface IMyService
{
    [OperationContract]
    [WebGet(UriTemplate = "deliveries", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json)]
    IQueryable<TableDelivery> GetDeliveries();
}

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class MyService : IMyService
{
    ...
}