CODEWITHSUNDEEP
mysqldjangodjango-modelsdjango-migrations
Almad
Almad

Reputation: 5893

How To Migrate IntegerField To ForeignKey

I have a legacy database I am migrating towards Django.

I have model like this:

class MyModel(models.Model):
    other_id = models.IntegerField()

This is an existing table filled with valid data. I want to migrate to

class MyModel(models.Model):
    newbie = models.ForeignKey(
        OtherModel,
        on_delete=models.CASCADE,
        db_constraint=False,
        db_column="other_id",
    )

However, the generated migration keeps insisting on adding the already existing field and than dropping it:

python manage.py sqlmigrate app 0069

BEGIN;
--
-- Add field
--
ALTER TABLE `mymodel` ADD COLUMN `other_id` integer DEFAULT 1 NOT NULL;
ALTER TABLE `mymodel` ALTER COLUMN `other_id` DROP DEFAULT;
--
-- Remove field
--
ALTER TABLE `mymodel` DROP COLUMN `other_id`;

Is there a way to convince Django to treat the field as ForeignKey without this exercise? I'd like to avoid a need to --fake the migration.

Upvotes: 0

Views: 509

Answers (1)

Almad
Almad

Reputation: 5893

Per suggestion, it helps to just write your own migration:

operations = [
    migrations.AlterField(
        model_name="mymodel",
        name="other_id",
        field=models.ForeignKey(
            on_delete=django.db.models.deletion.CASCADE,
            related_name="other",
            to="ddcz.UserProfile",
            db_column="other_id",
            db_constraint=False,
        ),
    ),
    migrations.RenameField("MyModel", "other_id", "other"),
]

Upvotes: 2

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