What is WCF Data Service?

Yes, WCF Data Service is used to expose data to clients/consumers like a way of REST nature.

menas REST uses Http vebs like: GET,PUT,DELETE,SET , as well as WCF Data Services using OData

Protocol to exchange data between Service and Clients.

OData Protol uses the simple verbs to expose Entities/Resoures/data to clients in REST based nature.

ADO.NET Entity Framework allows u work with OData Protol communication using WCF Data Service.

once our Entity Data Model is prepared then which ready to Consume using OData Protol communication.

Ex :

yes, just i created one console appliation(best take Class Library) which the name of EntityFrameworkDemo  then i add ADO.NET
Entity Model temple ---->
Using Northwind database.

Now I am created one asp.net Empty asp.net website to expose our service to clients --->ExposeWcfDataService
then add the Refernce of my Data/Entities/Resoures using Add Reference.---

EntityFrameworkDemo to our ExposeWcfDataService. then everythis is ready. so Know we have prepare

wcf Data Service --> RightClick ---ExposeWcfService(asp.netempty webseit). then add WCF Data Service templet to project.

now we added a service with the name is :WcfNorthwindDataService
asdf
we know host the service in wcf using : ServiceHost class.  like in

DataServiceHost also but here use host the service for selfHosting.

DataService<T> is a genic type which can host the service.which entry point for our
ADO.net Data Services.

like here

public class WcfNorthwindDataService : DataService<EntityFrameWorkDemo.NorthwindEntities>

    {

        // This method is called only once to initialize service-wide policies.

        public static void InitializeService(DataServiceConfiguration config)

        {

          

            config.SetEntitySetAccessRule("*", EntitySetRights.All);

            config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;

        }

    }

Here :

setEntitySetAccessRule--> * means i want expose all entities/resoues to client. Entity

EntitySetRights: clients can perform all operartion on my entities/resources.

 now add the Cofing from our library/northwind config from our app.config then added in our
WcfNorthwindDataService in web.config

<connectionStrings>

<add name="NorthwindEntities" connectionString="metadata=res://*/Northwind.csdl|res://*/Northwind.ssdl|res://*/Northwind.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=GM-VHOP-KASI;Initial Catalog=NORTHWND;Persist Security Info=True;User ID=sa;Password=zolt123$;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />

</connectionStrings>

now Run our wcf Data service----> WcfNorthwindDataService (.svc)

Internet Explorer: Internet Options--Content---Feed and web Slice Setting to 

disable  :  Turn on feed Reading view // to view the contet---> unchek if it is checked mode.

   now my WCF Data Service is running then Client can consume the this Service.

we have many commands called as $ Commands to query the data in Auto xml format in browser support

like

http://localhost:3790/WcfNorthwindDataService.svc/Customers-----> all customers

http://localhost:3790/WcfNorthwindDataService.svc/Customers

for specific we have top(1),skip()....methods and overby, desc,...ect $ command available to check the data.

Now Consume the Service.

create the Client(WCFDataServiceClient) the add the above Service reference. 

sdfa

yes, service Reference is added at client.then expand ServiceReferenc1---find the service.edmx file at client.

means the Sehema/Conceptual model is available to client to work with service.

so as per our 

Conceptual Sechma to Client

onfig.SetEntitySetAccessRule("*", EntitySetRights.All);---at service hosting 

client can perform any operation at every entitiy.[categories,Products,...ect].

Ex:

class Program

    {

        static void Main(string[] args)

        {

           Uri uri=new Uri("http://localhost:3790/WcfNorthwindDataService.svc/");

            NorthwindEntities proxy = new NorthwindEntities(uri);

 MyPerson person = new MyPerson { ssname = "WCF Data Service", abcd = "Excellent" };

            proxy.AddObject("MyPersons", person);

            try

            {

                proxy.SaveChanges();

                Console.Write("Inserted succefully....");

            }

            catch (Exception)

            {

                Console.Write("Error Occured");

            }

            Console.Read();

        }

    }

output 

Few points regarding WCF Data Services:

using WDS we can query(retrive) the data  URI based.  // REST style

using WDS we can sent/retrive the data in Auto-XML based/ JSON based.

using OData Model browser we can able view Designer view also.// tables with their relations.

using New Versions we can able
DataServiceProtocolVersion.v1/v2  ...retriveal command in browser also improved.