Atomic increment of a counter in django

Question

I\'m trying to atomically increment a simple counter in Django. My code looks like this:

from models import Counter
from django.db import transaction

@trans         


        

Answer 1

New in Django 1.1

Counter.objects.get_or_create(name = name)
Counter.objects.filter(name = name).update(count = F('count')+1)

or using an F expression:

counter, _ = Counter.objects.get_or_create(name = name)
counter.count = F('count') +1
counter.save( update_fields=["count"] )

Remember to Specify Which fields to update, Or you might encounter race conditions on other possible fields of the model!

A topic on the race condition associated with this approach has been added to the official documentation.