Django self-recursive foreignkey filter query for all childs

django model recursive-query
Ahsan picture Ahsan · Jan 18, 2011 · Viewed 19.2k times · Source

I have this model with a self referencing Foreign Key relation:

class Person(TimeStampedModel):
    name = models.CharField(max_length=32)
    parent = models.ForeignKey('self', null=True, blank=True, related_name='children')

Now I want to get all the multi level children for a person. How do I write a Django query for it? It needs to behave like recursive function.

Answer

sunn0 picture sunn0 · Jan 18, 2011

You can always add a recursive function to your model:

EDIT: Corrected according to SeomGi Han

def get_all_children(self, include_self=True):
    r = []
    if include_self:
        r.append(self)
    for c in Person.objects.filter(parent=self):
        _r = c.get_all_children(include_self=True)
        if 0 < len(_r):
            r.extend(_r)
    return r

(Don't use this if you have a lot of recursion or data ...)

Still recommending mptt as suggested by errx.

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