问题
I have two threads, one which runs something like update t set ColA=foo and the other runs update t set ColB=foo. If they were doing raw SQL statements there would be no contention, but since Django gets and saves the entire row, a race condition can occur.
Is there any way to tell Django that I just want to save a certain column?
回答1:
You are correct that save will update the entire row but Django has an update which does exactly what you describe.
https://docs.djangoproject.com/en/stable/ref/models/querysets/#update
回答2:
Update old topic.
Now, we have update_fields argument with save:
If save() is passed a list of field names in keyword argument update_fields, only the fields named in that list will be updated.
https://docs.djangoproject.com/en/stable/ref/models/instances/#specifying-which-fields-to-save
product.name = 'Name changed again'
product.save(update_fields=['name'])
回答3:
I think your only option to guarantee this is to write the raw SQL by hand by using Manager.raw() or a cursor depending on which one is more appropriate.
来源：https://stackoverflow.com/questions/7528683/django-partial-update