Re: [Django] #31343: Foreign key constraint to MTI child model is lost if the child model's parent was changed. (was: Foreign key constraint to a multi-table inheritance child model is lost if the child model's parent is changed)

[Django]

#31343: Foreign key constraint to MTI child model is lost if the child model's
parent was changed.
-------------------------------------+-------------------------------------
     Reporter:  Antonis              |                    Owner:  nobody
  Christofides                       |
         Type:  Bug                  |                   Status:  closed
    Component:  Migrations           |                  Version:  master
     Severity:  Normal               |               Resolution:  duplicate
     Keywords:                       |             Triage Stage:
                                     |  Unreviewed
    Has patch:  0                    |      Needs documentation:  0
  Needs tests:  0                    |  Patch needs improvement:  0
Easy pickings:  0                    |                    UI/UX:  0
-------------------------------------+-------------------------------------
Changes (by felixxm):

 * status:  new => closed
 * resolution:   => duplicate


Comment:

 Thanks for this ticket. I think it's another use case for
 `AlterModelBases`, see #23521. I was able to migrate this properly with
 the following operations:
 {{{
     operations = [
         migrations.CreateModel(
             name='CommercialPlace',
             fields=[
                 ('place_ptr', models.OneToOneField(auto_created=True,
 on_delete=django.db.models.deletion.CASCADE, parent_link=True,
 primary_key=True, serialize=False, to='places.Place')),
                 ('business_name', models.CharField(max_length=50)),
             ],
             bases=('places.place',),
         ),
         migrations.AlterModelBases('restaurant',
 ('places.commercialplace',)),
         migrations.RenameField('restaurant', 'place_ptr',
 'commercialplace_ptr'),
         migrations.AlterField(
             model_name='restaurant',
             name='commercialplace_ptr',
             field=models.OneToOneField(auto_created=True,
 on_delete=django.db.models.deletion.CASCADE, parent_link=True,
 primary_key=True, serialize=False, to='places.CommercialPlace'),
         ),
     ]
 }}}

-- 
Ticket URL: <https://code.djangoproject.com/ticket/31343#comment:1>
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