Django-mptt initial migrations when using Django's Group model

Question

I was having a look at django-mptt and found out that I can use use it with Django's built-in Group model. So, I followed the steps mentioned in documentation

import mptt
from mptt.fields import TreeForeignKey
from django.contrib.auth.models import Group

# add a parent foreign key
TreeForeignKey(Group, blank=True, null=True, db_index=True).contribute_to_class(Group, 'parent')

mptt.register(Group, order_insertion_by=['name'])

While running the initial migrations I got messages saying that the four fields viz. level, lft, rght, tree_id added by MPTTModel on existing Group model needed default values. All of them were PositiveIntegerField, I wonder what are the valid default values I can provide without corrupting the database

Did you solve your problem? I am getting the same issue – user5594493 Feb 08 '16 at 07:27 — user5594493, Feb 08 '16 at 07:27

score -1 · Answer 1 · answered Jun 28 '16 at 14:39

TreeForeignKey(Group, blank=True, null=True, db_index=True).contribute_to_class(Group, 'parent')
PositiveIntegerField(default=0, editable=False, db_index=True).contribute_to_class(Group, 'level')
PositiveIntegerField(default=0, editable=False, db_index=True).contribute_to_class(Group, 'lft')
PositiveIntegerField(default=0, editable=False, db_index=True).contribute_to_class(Group, 'rght')
PositiveIntegerField(default=0, editable=False, db_index=True).contribute_to_class(Group, 'tree_id')
mptt.register(Group,  order_insertion_by=['name'])

Please see [how to answer](http://stackoverflow.com/help/how-to-answer) questions on SO. — techspider, Jun 28 '16 at 14:56

Django-mptt initial migrations when using Django's Group model

1 Answers1