WCF Data Services saving relational entities

I'm trying to save an object back to the database via WCF, like so (pseudo code):

var Contact = new Contact
{
    Id = Guid.NewGuid(),
    Name = "Test",
    Address = new Address
    {
        Id = Guid.NewGuid(),
        Postcode = "blah"
    }
};

In my model the relationship is 1 to 1 with Conta开发者_开发百科ct and Address but doing this fails:

DB.AddToContacts(Contact);
DB.SaveChanges();

Complaining the relationship isn't met and can't be empty. So I tried this approach:

DB.AddToContacts(Contact);
DB.AddToAddresses(Contact.Address);
DB.AddRelatedObject(Contact, "Address", Contact.Address);
DB.SaveChanges();

but now I get "AddRelatedObject method only works when the sourceProperty is a collection.".

My question: how do I save back a related entity easily via WCF?

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This might not be the best answer, but it worked for me... When trying to create an related object in WCF Data Services, you have to set the "back-reference" manually ( this is where the behaviour differs from the normal usage of EF )..

So, in your case you would have to set sth like:

var Contact = new Contact
{
  Id = Guid.NewGuid(),
  Name = "Test",
  Address = null
};

var address = new Address
{
      Id = Guid.NewGuid(),
      Postcode = "blah",
      // This is important
      Contact = Contact
};

contact.Address = address;
DB.AddToContracts(Contract);
DB.SaveChanges();

This is pretty annoying... And as i got this experience the "hard" way.. WCF Data Services is slow as s**t and selecting hierarchical data ( such as Order - OrderPosition - Product ) is a real pain... you may consider using sth. different for latency-relevant scenarios...

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I finally got it to work by doing this:

DB.AddToAddresses(Client.Address);
DB.AddToClients(Client);

DB.SetLink(Client, "Address", Client.Address);

DB.SaveChanges();

That is 4 individual calls over the wire to the WCF service to add a relational object. At the end of it all I'll be making 14 calls, eek!