Comment by msla

It seems like narrow tables solve having NULLs in the tables you store, but they do nothing about NULLs in the tables you create using, say, a LEFT JOIN. Like, if you create a database with Name, Postnomials, and Prenomials, some people don't have Postnomials or Prenomials, so even if you create three narrow tables, when you JOIN them all to form the full polite addresses, you'll end up with NULLs in the result of that JOIN.