Opened 7 years ago
Last modified 7 years ago
#29398 closed Cleanup/optimization
Cascade deletion doesn't invoke .delete() on the cascaded objects — at Version 1
Reported by: | Daniel Quinn | Owned by: | nobody |
---|---|---|---|
Component: | Documentation | Version: | 1.11 |
Severity: | Normal | Keywords: | delete cascade |
Cc: | Triage Stage: | Accepted | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
I understand that when using .delete()
on a queryset, the object(s) in question won't have their .delete()
method executed. However, if you're explicitly calling .delete()
on an object, I would expect that this would in turn call .delete()
on any cascaded objects as well, and this appears not to be the case. Some example code for illustration:
class User(models.Model): name = models.Charfield(max_length=16) def delete(self, *args, **kwargs): print("This is executed") super().delete(*args, **kwargs) class Business(models.Model): user = models.ForeignKey(User, on_delete=models.CASCADE) def delete(self, *args, **kwargs): print("This isn't executed :-(") super().delete(*args, **kwargs) # This will run User.delete() and delete the associated business, but *not* execute Business.delete() User.objects.first().delete()
It's unclear whether this is a bug or intentional, but I didn't see anything about this in the documentation and it surprised me today, so I thought I would mention it. I generally don't like signals (too much magic) but is that the preferred method for handling deletion special cases?