Probable Bug, foreign key to a database view.

[Sandeep Harlalka]

class View(models.Model):

    field = models.CharField(max_length=4)

    class Meta:

         managed=False

          db_table = 'view' #database view

class Child(models.Model):

  view = models.ForeignKey(View, on_delete=models.CASCADE, to_field='field', db_constraint=False)

makemigrations on above will have the view field of type integer while it should be varcher(4)

This is my first post to the forum. Please inform if something is amiss.

Thank You

[Alexandru M.]

Does it behave the way you're expecting it to behave if you declare field as models.CharField(max_length=4, primary_key=True)?

[Adam Johnson]

Sandeep - it's best to report bugs as tickets.

Anyway, I checked this out for you and I don't see the problem. I started a project, and added the code you suggested as models, ran makemigrations, and saw this error:

$ ./manage.py makemigrations core
SystemCheckError: System check identified some issues:

ERRORS:
core.Child.view: (fields.E311) 'View.field' must be unique because it is referenced by a foreign key.
HINT: Add unique=True to this field or add a UniqueConstraint (without condition) in the model Meta.constraints.

After adding primary_key=True as Alexandru suggests, the migration created successfully:

$ ./manage.py makemigrations core
Migrations for 'core':
  example/core/migrations/0001_initial.py
    - Create model View
    - Create model Child

The migration looks correct:

# Generated by Django 4.0.3 on 2022-04-05 15:40

from django.db import migrations, models
import django.db.models.deletion


class Migration(migrations.Migration):

    initial = True

    dependencies = []

    operations = [
        migrations.CreateModel(
            name="View",
            fields=[
                (
                    "field",
                    models.CharField(max_length=4, primary_key=True, serialize=False),
                ),
            ],
            options={
                "db_table": "view",
                "managed": False,
            },
        ),
        migrations.CreateModel(
            name="Child",
            fields=[
                (
                    "id",
                    models.BigAutoField(
                        auto_created=True,
                        primary_key=True,
                        serialize=False,
                        verbose_name="ID",
                    ),
                ),
                (
                    "view",
                    models.ForeignKey(
                        db_constraint=False,
                        on_delete=django.db.models.deletion.CASCADE,
                        to="core.view",
                    ),
                ),
            ],
        ),
    ]

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