Entity Framework 4.1: Possible to save a single table out of a data context containing multiple tables? - asp.net-mvc-3

Question

I have a chicken and egg problem, it's trivial, so I thought I would ask what's the normal pattern to save an aggregate root where all the primary keys are identity fields.
I have a typical contact entity:
Customer {
HomeAddress {
}
WorkAddress {
}
}
where both addresses are stored in the address table and the only primary key is the identity field. We check all fields against each other to keep unique address records.
Here's the problem:
I need to retrieve the Address identity field to hookup the foreign keys, so I save the Address record prior to saving the Customer record only if it's unique, otherwise I load that existing Address.
If Address is in the same DC as Customer, then customer saves too prematurely (not all records are set.)
If Address is in a separate DC, then it doesn't hookup to the Customer record that has it's own DC because you cannot have an entity associated with two DCs (can't open in one, then save in another.)
So my thinking is that I would need a separate repository for every Address, then separately load the address again in the other DC, making redundant calls to the database for the same information.
Is there a way to partially save records in a data context / container in Entity Framework 4.1? For example, to save Address by itself while still being in the same DC?

Answer 1

The answer to your bold question is "No" as far as I can tell. The context is a unit of work and SaveChanges commits every new, changed or deleted object to the database in a single transaction. You cannot selectively say: Save only this or that object or save only entities in state Added and don't commit entities in state Modified or Deleted or something.
As a workaround you could try that:
using (var context1 = new MyContext())
{
Address address = context1.Addresses.Where(predicate).FirstOrDefault();
// if address != null it is attached now to context1
if (address == null)
{
// ... otherwise create new address in another context and save
using (var context2 = new MyContext())
{
address = new Address { Name = name, ... }
context2.Addresses.Add(address);
context2.SaveChanges();
} // context2 destroyed now and address is not attached to it anymore
// ... and attach to context1
context1.Addresses.Attach(address);
}
customer.HomeAddress = address;
// ...
context1.SaveChanges();
}
This way address is never attached to the two contexts at the same time. I am not sure though if this works.
Edit
I must add (because my code above looks so weird) that "normally" you could do all this in context1 alone. But I understood your point 2 this way that there is something happening in // ... (which I don't understand) before SaveChanges which prevents you to save the new address and the customer at the same time.