How to stop WCF data Service to fetch data when SavingChanges (during update)

I am trying to update an entity from a WCF client as follows:

        Ctxt.MergeOption = MergeOption.NoTracking;
        var q = Ctxt.Customers.Where(p => p.MasterCustomerId == "JEFFERSON").Select(o => o);
        //DataServiceCollection<Customer> oCustomers = new DataServiceCollection<Customer>(q, TrackingMode.None);
        DataServiceCollection<Customer> oCustomers = new DataServiceCollection<Customer>(q);
        oCustomers[0].FirstName = "KEFFERSON";
        //Ctxt.SaveChanges(SaveChangesOptions.ReplaceOnUpdate);
        //ctxt.SaveChangesDefaultOptions = SaveChangesOptions.ReplaceOnUpdate;
        Ctxt.SaveChanges();

When I try to save the modified entity, it first tries to load that entity using a select query (to database) and then issues update statement to database.

In my case, I simply want to have the entity to be directly updated in the database without fetching it first. I don't mind if it overwrites the data in database

I tried the following at WCF service:

protected override EF.Model.DataModel.PersonifyEntities CreateDataSource()
{
    var ctxt = new EF.Model.DataModel.PersonifyEn开发者_运维百科tities();
    ctxt.Customers.MergeOption = System.Data.Objects.MergeOption.NoTracking;
    ctxt.ContextOptions.ProxyCreationEnabled = false;
    ctxt.ContextOptions.LazyLoadingEnabled = false;
    return ctxt;
}

But, no luck. Can anyone help me on this?

For WCF DataServices, the client can only update entities that it tracks. So it has to have the entity downloaded in the client before it can make any changes and save it back. Thats why you see the fetch (I am assuming that this is the first fetch that you are seeing for that specific entity) before the update. Hope this helps.