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djangomodelrecursive-query

Django self-recursive foreignkey filter query for all childs


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.


Solution

  • 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.

    EDIT: 2021 since this answer is still getting attention :/

    Use django-tree-queries instead!