SQL Server has a variety of means of making such a join fast. If your business rules allow it, this is the way to go. Allowing the referencing column to have NULLs will create the same requirement, except that the user will also have the option ofanbsp;...
|Title||:||Beginning Microsoft SQL Server 2012 Programming|
|Author||:||Paul Atkinson, Robert Vieira|
|Publisher||:||John Wiley & Sons - 2012-04-16|