title: Constraint violation / Duplicate key when reindexing Magento
body: <p>I am using Magento CE 1.6.2 and I have a problem with my reindexer ( the  url_rewrite )</p>
  
  <pre><code>php shell/indexer.php --reindex catalog_url
  Catalog URL Rewrites index process unknown error:
  exception 'PDOException' with message 'SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '33432700_1343855802-0-1' for key 'UNQ_CORE_URL_REWRITE_ID_PATH_IS_SYSTEM_STORE_ID'' in /home/website/public_html/lib/Zend/Db/Statement/Pdo.php:228
  </code></pre>
  
  <p>When I truncate the core_url_rewrite... and hit the indexer via the backend for the first time, everything is fine, and my url rewrites are stored in the core_url_rewrites...
  But if I start the indexer a second time (without flushing the table), I get an error of duplicate key.</p>
  
  <p>Here is a screen shot of my table: <a href="https://www.dropbox.com/s/6v9uawp5v437w3h/seo_Magewroks.png" rel="nofollow noreferrer">https://www.dropbox.com/s/6v9uawp5v437w3h/seo_Magewroks.png</a></p>
  
  <p>note: UNQ_CORE_URL_REWRITE_ID_PATH_IS_SYSTEM_STORE_ID is an index key</p>
  
  <p>How can I find the source of the problem? </p>