Handling One to One foreign key relationships - LightSwitch

I am currently trying to add a one to one foreign key relationship in LightSwitch. It is be开发者_如何学编程tween an ID and a username. Ideally I would be able to show the username wherever the related ID is displayed. Any help much appreciated.

one to one relationships are not supported. What is supported is one to one or zero mappings. See http://msdn.microsoft.com/en-us/library/ff852044.aspx#Multiplicity