Getting next and previous objects in Django

Question

I'm trying to get the next and previous objects of a comic book issue. Simply changing the id number or filtering through date added is not going to work because I don't add the issues sequentially.

This is how my views are setup and it WORKS for prev_issue and does return the previous object, but it returns the last object for next_issue and I do not know why.

def issue(request, issue_id):     issue = get_object_or_404(Issue, pk=issue_id)     title = Title.objects.filter(issue=issue)     prev_issue = Issue.objects.filter(title=title).filter(number__lt=issue.number)[0:1]     next_issue = Issue.objects.filter(title=title).filter(number__gt=issue.number)[0:1] 

Answer 1

Add an order_by clause to ensure it orders by number.

next_issue = Issue.objects.filter(title=title, number__gt=issue.number).order_by('number').first() 

Answer 2

I know this is a bit late, but for anyone else, django does have a nicer way to do this, see https://docs.djangoproject.com/en/1.7/ref/models/instances/#django.db.models.Model.get_previous_by_FOO

So the answer here would be something something like

next_issue = Issue.get_next_by_number(issue, title=title) 

Django managers to do that with a bit of meta class cleaverness.