How to cascade an update in a one-to-many relationship?
<p>I think this is best explained with an example.</p>

<pre><code>class GrandParent(models.Model):
    pass

class Parent(models.Model):
    grandparent = models.ForeignKey(GrandParent, null=True, blank=True, default=None)    

class Child(models.Model):
    parent = models.ForeignKey(Parent, null=True, blank=True, default=None)
    grandparent = models.ForeignKey(GrandParent, null=True, blank=True, default=None)    
</code></pre>

<p>So we have three classes. Child has a foreign key to Parent and GrandParent, and Parent has a foreign key to GrandParent.</p>

<p>In the Django Admin area I click on a Parent record (P1) and set its foreign key to a GrandParent record (GP1).</p>

<p>I would like this to cascade to all the Child records. In other words, every Child record which already has a foreign key to P1 should automatically get a foreign key to GP1.</p>

<p>Is there a Django way to do this?</p>

<p>Thank you.</p>