Python/Django Modeling Question

Question

What is the best way to have many children records pointing to one parent record in the same model/table in Django?

Is this implementation correct?:

class TABLE(models.Model):
    id = models.AutoField(primary_key=True)
    parent = models.ForeignKey("TABLE", unique=False)

Unless I'm missing something, you don't need the id field, that'll be generated for you automatically as an auto-incrementing primary key field. — Dominic Rodger
– Dominic Rodger, Commented Apr 13, 2009 at 18:43
Also, the default value of unique is False, so you don't need that — Dominic Rodger
– Dominic Rodger, Commented Apr 13, 2009 at 18:44

Powerlord · Accepted Answer · 2009-04-13 18:40:42Z

10

Django has a special syntax for ForeignKey for self-joins:

class TABLE(models.Model):
    id = models.AutoField(primary_key=True)
    parent = models.ForeignKey('self')

Source (second paragraph)

answered Apr 13, 2009 at 18:40

Powerlord

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Comments

Community · Accepted Answer · 2017-05-23 12:20:37Z

2

Two things:

First, you need to allow the possibility of a null value for parent, otherwise your TABLE tree can have no root.

Second, you need to worry about the possibility of "I'm my own grandpa." For a lively discussion, see here.

CommunityBot

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answered Apr 13, 2009 at 18:45

David Berger

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