setting db_column to same value as another column should not validate

[Anssi Kääriäinen]

Consider having a model

class FooBar(models.Model):
    foo = models.IntegerField()
    bar = models.IntegerField(db_column='foo')
    class Meta:
        db_table = 'foobar'

This does not raise any validation errors, even though the model clearly is not valid.

[Thomas Ashelford]

Agreed, let's fix it. I'll work up a patch.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Tim Graham]

Seems like this would be a fairly easy addition to django/core/management/validation.py with a test in django/tests/invalid_models/tests.py.

[Helen Sherwood-Taylor]

Working on this at the PyConUK Django sprint

[Helen Sherwood-Taylor]

Should it be valid to do something like this?

class FooBar(models.Model):
    foo = models.IntegerField(db_column='bar')
    bar = models.IntegerField(db_column='foo')
    class Meta:
        db_table = 'foobar'

i.e. should setting db_column on the first column 'free up' the name so the second one can use it?

[Helen Sherwood-Taylor]

Consensus on #django-dev was that this should be a valid model.

[Helen Sherwood-Taylor]

I have created a pull request which fixes this:

​https://github.com/django/django/pull/1664

[Tim Graham <timograham@…>]

In 41167645b1039067127fa215d4d28296bfa4cfdc:

Fixed #14028 - Added validation for clashing db_columns.

Thanks akaariai for the suggestion.