title: PDO Event Constants
body: <p>i've a little doubt about on PHP with PDO constants.
  How i use it? There is no documentation and no example and no questions here about it.</p>
  
  <p>Did some one put this into work knows how to use it?</p>
  
  <pre><code>PDO::PARAM_EVT_FREE (integer)
  
   Deallocation event
  
  PDO::PARAM_EVT_EXEC_PRE (integer)
  
   Event triggered prior to execution of a prepared statement.
  
  PDO::PARAM_EVT_EXEC_POST (integer)
  
   Event triggered subsequent to execution of a prepared statement.
  
  PDO::PARAM_EVT_FETCH_PRE (integer)
  
   Event triggered prior to fetching a result from a resultset.
  
  PDO::PARAM_EVT_FETCH_POST (integer)
  
   Event triggered subsequent to fetching a result from a resultset.
  
  PDO::PARAM_EVT_NORMALIZE (integer)
  
   Event triggered during bound parameter registration allowing the driver to normalize the parameter name.
  </code></pre>
  
  <p><a href="http://php.net/manual/en/pdo.constants.php" rel="nofollow">http://php.net/manual/en/pdo.constants.php</a></p>