title: How to choose my primary key?
body: <p>I found this reading material on <a href="http://databases.about.com/od/specificproducts/a/primarykey.htm" rel="noreferrer">choosing a primary key</a>.</p>
  
  <ul>
  <li>Is there a guide / blog post on how to choose the primary key for a given table? </li>
  <li>Should I use a auto-incremented/generated key, or should I base the primary key on the data being modeled (assuming it has a truly unique field)?</li>
  <li>Should the primary key always be long for performance's sake, or can I take an external unique id as primary key, even if it's a string?</li>
  </ul>