title: Django and Sqlite Concurrency issue
body: <p>I've done a bit of reading related to the concurrency issues with sqlite, but I don't see how they'd apply to Django since it's inherently single threaded. I'm not using any multiprocess modules either. I have absolutely no experience with concurrent programming either, so if someone can identify WHY the following code is causing an OperationalError: 'database is locked' I'd be grateful.</p>
  
  <p>views.py  </p>
  
  <pre><code>def screening(request, ovramt=None):
  errors = []
  if request.method == "POST":
      form = ScreeningForm(request.POST)
      if form.is_valid():
         print "Woo valid!!"
      return HttpResponse()
  
  else: # GET            
      if ovramt is None:
          o = Ovramt.objects.select_related(depth=1).latest("date_completed")
          print "found?"
          print o.id
      else:
          try:
              o = Ovramt.objects.select_related(depth=1).get(id=ovramt)
          except:
              errors.append("OVRAMT NOT FOUND") 
  
  
      if o.residents.count() &lt;= 0:
          o.add_active_residents()
      residents = list(o.residents)
  </code></pre>
  
  <p>models.py</p>
  
  <pre><code>def add_active_residents(self):
      ssa_res = SSA_Resident.objects.select_related(depth=1).filter(ssa=self.ssa, active=True)
      for r in ssa_res:
          self.residents.add(r.resident) # Fails Here
      self.save()
  </code></pre>
  
  <p>The add_active_residents method works fine, until it is called from the views module. Is there an open connection to the database open in the view which prevents writing from the model? Does someone have an explanation why this code will error?</p>