A unique index allows for 1 NULL value, a primary key doesn't allow NULLS. How will you match the NULL when nothing is equal to NULL not even another NULL.
I have the same problem. However, in my case, the column that I'm attempting to link to is not the primary key. Hence, it won't work.
The EDMX file won't compile saying that it has to link to a primary key. This makes sense. The only reason I'm running into the problem is that I'm dealing with a legacy database that was poorly designed.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.