Django complex queries

I need to craft a filter for an object that checks date ran开发者_如何学Goges. Right now I'm performing a very inefficient loop which checks all the objects. I would like to simplify this to a database call.

The logic is you have a start and an end date objects. I need to check if the start OR the end is within the range of an appointment.

if (start >= appointment.start && start < appointment.end) || 
   (end > appointment.start && end <= appointment.end)

I could do this in SQL, but I'm not as familiar with the Django model structure for more complex queries.

You need Q objects for & and OR operators and the range field lookup type

Q Object: http://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects

range: http://docs.djangoproject.com/en/dev/ref/models/querysets/#range

Entry.objects.filter(Q(start__range=(appointment.start, appointment.end)) | 
    Q(end__range=(appointment.start, appointment.end)))

If an SQL BETWEEN, is not what you are looking for, you can always use specific combinations of Q objects to reproduce your conditions exactly:

Entry.objects.filter((Q(start__gte=appointment.start) & Q(start__lt=appointment.end)) | 
   (Q(end__gt=appointment.start) & Q(end__lte=appointment.end)))