title: How do you give your users a unique ID without using the primary key in the database?
body: <p>If I have 10,000 users and the primary key is a unique ID going from 1 to 10,000, is there a way to give them all a unique ID such that the original primary key cannot be inferred from it?</p>
  
  <p>For example, linking to your facebook profile or similar would be <a href="http://site.com/profile?id=293852" rel="nofollow">http://site.com/profile?id=293852</a></p>
  
  <p>Is it likely that the id there is the same as the primary key of their user in the database? I am struggling to think of a way to have two unrelated unique ID columns, because randomly generated ones would have to be unique. I imagine if it were possible to have a GUID using numbers only the length would be far too long.</p>
  
  <p>And ideas?</p>