I am a Django newbie and also interested in this question. >From reading the Django book http://www.djangobook.com/en/2.0/chapter05/, I see that the query 'Publisher.objects.order_by('name')[0:2]' maps to:
SELECT id, name, address, city, state_province, country, website FROM books_publisher ORDER BY name OFFSET 0 LIMIT 2; Also, Django delays execution of the db query until the result is actually required. Given the above two observations, I would think that both the type of accesses you mentioned will do exactly the same thing, which is to do a query with "OFFSET 0 LIMIT 1". To confirm this, you can use the django-devserver (https://github.com/ dcramer/django-devserver) with SQL queries enabled which will display every query made in real time. thanks, -pavan On Apr 14, 9:56 pm, NENAD CIKIC <nenad.ci...@gmail.com> wrote: > Hello! > I want to get just the top element of one queryset. SO I have > something as > qs=MyModel.objects.filter(...).order_by(..) > > and then use qs[0] and check some value > > I wonder now if i did the right thing or it is better to use .extra on > queryset. > Is the queryset object allocated for all objects, or is django/python > smarter than me and gets only the needed object? > > Should I maybe do directly > topObj=MyModel.objects.filter(...).order_by(..)[0] > > What is better? > Thanks > Nenad -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
