title: Questions on Auction Database Schema
body: <p>I was looking at the following <a href="http://www.databaseanswers.org/data_models/auction/index.htm" rel="nofollow noreferrer">db model</a> and I had some questions on it. I'm sure it's a good design as the guy behind it seems to be reasonably well qualified, although some things don't make sense:</p>
  
  <ol>
  <li>Why's he seperated out bidders and sellers? I thought you'd have users, and users can place bids and sell items. You'd have a bids table with a reference to user, and a auctions table, with reference to user table. He talks a lot in his tutorials about making sure models are scalable and ready for change (don't have a status column for instance, have statuses in another table and reference that) so what's up here?</li>
  <li>Why are their fields like "planned close date" and "winner". Isn't this data duplication, as the planned close date could be calculated using the last bid time (for acutions that use auto extend) and the winner is simply the last bid when the auction closes..? </li>
  </ol>
  
  <p>FYI: I'm trying to build my own auction site in PHP/MySQL from scratch and it's proving to be quite difficult, so tutorials on this would be great!</p>
  
  <p>Thanks!</p>