title: Could PDO::lastInsertId() be inaccurate?
body: <p>I've got a page calling a script via AJAX which could be asynchronously called multiple times simultaneously from the same parent page.  This script uses require_once to access a configuration script with the database handler.  Will the script call a unique instance of this handler each time, or if multiple copies are open will they all be using the same instance and causing undesirable results when I attempt to get the ID of the last insert from that instance of the script?</p>
  
  <p><strong>Just to be clear, this is the command I'm referencing:</strong></p>
  
  <pre><code>$DBH-&gt;lastInsertId()
  </code></pre>
  
  <p>Thanks!</p>