title: Is there ever a time where using a database 1:1 relationship makes sense?
body: <p>I was thinking the other day on normalization, and it occurred to me, I cannot think of a time where there should be a 1:1 relationship in a database.</p>
  <ul>
  <li><code>Name:SSN</code>?  I'd have them in the same table.</li>
  <li><code>PersonID:AddressID</code>?  Again, same table.</li>
  </ul>
  <p>I can come up with a zillion examples of 1:many or many:many (with appropriate intermediate tables), but never a 1:1.</p>
  <p>Am I missing something obvious?</p>