title: Storing date as integer
body: <ol>
  <li><p>I came across a database schema (instant messaging, <a href="http://www.9lessons.info/2013/05/message-conversation-database-design.html" rel="nofollow noreferrer">http://www.9lessons.info/2013/05/message-conversation-database-design.html</a>) where message's date + time is stored not as timestamp, but with an integer, like 123984347439.</p>
  <p>What's the point of this?</p>
  </li>
  <li><p>I found a couple of resources which store dates as integers, like 20151009. What are pros and cons of this approach in comparison native date + time specific formats of databases?</p>
  </li>
  </ol>