#26703: field automatically choosen as primary_key (primary_key=False do not
work)
-------------------------------------+-------------------------------------
Reporter: nbremond | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.9
(models, ORM) | Keywords: multi-table
Severity: Normal | inheritance, primary_key,
| OneToOneField
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
I tried to use multi-table inheritance with a OneToOne field to the parent
class in the child class but this field seems to be detected as
primary_key by Django (there is only one row in the database).
The field has the same type as the parent link automatically created by
Django and
the [https://docs.djangoproject.com/en/1.10/topics/db/models/#specifying-
the-parent-link-field doc on inheritance] tells that we can choose to use
a such field for the inheritance relation with `parent_link=True` but I
need the inheritance relation AND my other relation.
I tried to add `parent_link=False` but this don't change anything.
If I add `null=True` I got an error :
{{{
SystemCheckError: System check identified some issues:
ERRORS:
testapp.A.other: (fields.E007) Primary keys must not have null=True.
HINT: Set null=False on the field, or remove primary_key=True
argument.
from django.db import models
}}}
So I tried to add `primary_key=False` but that don't change anything.
There is a minimal code wich reproduce the error
models.py :
{{{
#!python
class Base(models.Model):
pass
class A(Base):
other=models.OneToOneField(Base,
parent_link=False,#do not change anything
primary_key=False,#do not change anything
null=True,#raise a SystemCheckError
related_name='other_base',
)
}}}
I can continue my project if I replace the `OneToOneField` by a
`ForeignKey` with `unique=True` but I have a warning with a hint to
replace the `ForeignKey` by a `OneToOneField` :
{{{
System check identified some issues:
WARNINGS:
testapp.A.other: (fields.W342) Setting unique=True on a ForeignKey has the
same effect as using a OneToOneField.
HINT: ForeignKey(unique=True) is usually better served by a
OneToOneField.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/26703>
Django <https://code.djangoproject.com/>
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