title: GUID as PK for DB2-400
body: <p>I have a table that does not have a PK and I need to add one.  </p>
  
  <p>I was just going to add an an auto incrementing int as the last column (the database is not fully SQL so where I add the column actually matters).</p>
  
  <p>I've heard talk of UID's a function that returns a unique identifier every time it is called so no two rows in any table that uses a UID would have the same unique identifier.  </p>
  
  <p>Does DB2400 (the DB2 on an AS400 or iSeries) have such a function?</p>