title: PDO bindParam Timestamp is not inserted
body: <p>I have following PHP code for inserting session data into a table called ds_session:</p>
  
  <pre><code>    // session does not exists create insert statement
      $insertSQL = 'INSERT INTO ds_session (session_id, user_agent, session_expire, date_created, session_data)
                  VALUES (:SESSION_ID, :USER_AGENT, :SESSION_EXPIRE, :DATE_CREATED, :SESSION_DATA)';
  
      $insertStmt = $this-&gt;pdo-&gt;prepare($insertSQL);
      $insertStmt-&gt;bindParam(':SESSION_ID', $id);
      $insertStmt-&gt;bindParam(':USER_AGENT', $_SERVER['HTTP_USER_AGENT']);
      $insertStmt-&gt;bindParam(':SESSION_EXPIRE', $time);
      $insertStmt-&gt;bindParam(':DATE_CREATED', time());
      $insertStmt-&gt;bindParam(':SESSION_DATA', $sessData);
      $insertResult = $insertStmt-&gt;execute();
  </code></pre>
  
  <p>My problem here is, that the params SESSION_EXPIRE and DATE_CREATED are not set. 
  The table definition looks like this: </p>
  
  <pre><code>CREATE TABLE `ds_session` (
    `session_id` varchar(32) NOT NULL default '',
    `user_agent` varchar(255) NOT NULL default '',
    `session_expire` datetime NOT NULL,
    `date_created` datetime NOT NULL,
    `session_data` longtext,
  PRIMARY KEY  (`session_id`),
  KEY `session_expire` (`session_expire`)
  ) ENGINE=MyISAM
  </code></pre>
  
  <p>What is the problem here? Am I doing something wrong with the PDOStatement?</p>