What's the best approach for handling deletion of an object with some validation before the object is deleted? For example, in my setup have two models - Game and Team (which are obviously related). Users should only be able to delete teams that are NOT tied to any games.
I created a form (without any fields) for deleting a team...
class TeamDeleteForm(ModelForm):
class Meta:
model = Team
fields = []
def clean(self):
# Check to see if this team is tied to any existing games
if self.instance.gameteams_set.exists():
raise ValidationError("This team is tied to 1 or more games")
return super().clean()
But then I realized that the class based view DeleteView doesn't have any sort of form_valid() method. Should I extend the generic FormView instead of DeleteView or is there a better approach that I'm missing?
I think the best approach will be overriding the model's delete method. For example:
class Team(models.Model):
...
def delete(self, *args, **kwargs):
if Game.objects.filter(team__pk= self.pk).exists():
raise Exception('This team is related to a game.') # or you can throw your custom exception here.
super(Team, self).delete(*args, **kwargs)