>What about an optional mailing address FK?
>
>Hi....most (but certainly not all) address tables are normalized in 1-many relationships....
>
>e.g. Person (PersonID)
> PersonAddress (PersonAddressID, PersonID, AddressTypeID, AddressLine1, City, etc., StartDate, EndDate, etc.)
>
>several variations on this, but you get the drift....
>
>So in this case, wouldn't be relevant.

In our database we have separate Address table, Person table and a Link table. Link table also has a type of the address field.