1..0 or 1 relationships in Entity Framework

I came across this problem today when migrating a project from VS 2008/.NET 3.5 to VS 2010 RC1/.NET 4.0. I don’t actually think it’s a VS 2010 thing, though. I have two entities A and B. There is a navigation property on A, and it can have either one or no instances of B. B’s foreign key is to A’s primary key (obviously) but B also has its own primary key. In Read post »