In Django how do I notify a parent when a child is saved in a foreign key relationship?

Question

I have the following two models:

class Activity(models.Model):
    name = models.CharField(max_length=50, help_text=\'Some help.\')
    entity = models.ForeignKe         


        

Answer 1

What's wrong with the following?

class Cancellation( models.Model ):
    blah
    blah
    def save( self, **kw ):
        for a in self.activity_set.all():
            a.somethingChanged( self )
        super( Cancellation, self ).save( **kw )

It would allow you to to control the notification among models very precisely. In a way, this is the canonical "Why is OO so good?" question. I think OO is good precisely because your collection of Cancellation and Activity objects can cooperate fully.