title: Persistent data with finer granularity than a session in django
body: <p>Suppose that a staff member using a web site can exchange tickets for a customer.  It is convenient to store data about the multi-view exchange in the session.  But more than one exchange might be going on at the same time.</p>
  
  <p>One way to keep track of the separate data in the session is to create a sub-session key and use that to access the session data.  This key would need to be part of the view as a hidden input or it would need to be in the URL.  This all gets pretty messy and the hidden variable method isn't great since redirects might occur during the exchange.</p>
  
  <p>Is there a clean way to do this?</p>