Subsonic foreign key returning collection?

I'm just writing my first "Hello World" program using Subsonic, for which I've thrown together a simple little Customer/Invoice/InvoiceItem/Product database.

The connection was successfully made to the DB, and it generated all the right ActiveRecord classes. But for some reas开发者_运维知识库on, the Invoice class has a property called Customers, which returns a collection of Customer objects, even though the Invoice table has a CustomerID field which has a foreign key to the Customer table. I would have expected a Customer property returning a single Customer object.

Same thing is happening for all of my FKs. I must be doing something wrong - but what?

That is expected behavior. The first (and only) item in the Invoice.Customers collection will be the foreign key related Customer object.