AutoField has AUTO_INCREMENT while IntegerField does not so if the
migration is working correctly, I think its purpose is to drop the
AUTO_INCREMENT.
I'm reluctant to continue investigation as you're using an old version of
Django and many bugs have been fixed since then. If you can reproduce a
problem with Django 2.2 alpha and a fresh database, feel free to create a
ticket if you can't find an existing ticket.
On Friday, February 1, 2019 at 8:44:47 AM UTC-5, Carsten Fuchs wrote:
>
> Dear Django group,
>
> using a model like this:
>
> ```
> class Kostenstelle(models.Model):
> id = models.AutoField(primary_key=True)
> name = models.CharField(max_length=60, blank=True)
> # ... omitted fields
>
> class Meta:
> db_table = 'kostenstelle'
> ```
>
> I replaced the `id` line with
>
> ```
> id = models.IntegerField(primary_key=True, help_text="...")
> ```
>
> (This was a while ago, using Django 1.11.1.)
> Running `manage.py makemigrations` created two migration files, numbers
> 0022 and 0023:
>
> ```
> # Migration 0022.
> class Migration(migrations.Migration):
>
> dependencies = [
> ('Lori', '0021_alter_Vortraege_jahr'),
> ]
>
> operations = [
> migrations.AlterField(
> model_name='kostenstelle',
> name='id',
> field=models.IntegerField(primary_key=True, serialize=False),
> ),
> ]
>
> # Migration 0023.
> class Migration(migrations.Migration):
>
> dependencies = [
> ('Lori', '0022_alter_Kostenstelle_id'),
> ]
>
> operations = [
> migrations.AlterField(
> model_name='kostenstelle',
> name='id',
> field=models.IntegerField(help_text='...', primary_key=True,
> serialize=False),
> ),
> ]
> ```
>
> This used to work properly with the Oracle DB backend, but today, using
> Django 1.11.18 with MySQL backend, there are problems:
> Running `./manage.py sqlmigrate Lori 0023` shows, as expected, an empty
> commit. With comments and newlines stripped: `BEGIN; COMMIT;`
>
> I had expected `./manage.py sqlmigrate Lori 0022` to show an empty commit
> as well, as ttbomk, it doesn't imply any changes to the table schema.
> However, a lot of SQL statements were generated. Here the complete output,
> which also covers Foreign Keys that I omitted above:
>
> ```
> (Zeiterfassung) carsten@black-steel-ubuntu:~/Zeiterfassung$ ./manage.py
> sqlmigrate Lori 0022_alter_Kostenstelle_id
> BEGIN;
> --
> -- Alter field id on kostenstelle
> --
> ALTER TABLE `kostenstelle` DROP FOREIGN KEY
> `kostenstelle_parent_id_d0c73a18_fk`;
> ALTER TABLE `Lori_oeffnungszeiten` DROP FOREIGN KEY
> `Lori_oeffnungszeiten_kst_id_54e15381_fk`;
> ALTER TABLE `Lori_vertragsverlauf` DROP FOREIGN KEY
> `Lori_vertragsverlauf_kostenstelle_id_59f33815_fk`;
> ALTER TABLE `Lori_userkstzuordnung` DROP FOREIGN KEY
> `Lori_userkstzuordnung_kostenstelle_id_ac2cc3c0_fk`;
> ALTER TABLE `Lori_pekosollstd` DROP FOREIGN KEY
> `Lori_pekosollstd_kst_id_6b0156f7_fk`;
> ALTER TABLE `kostenstelle` MODIFY `id` integer NOT NULL;
> ALTER TABLE `kostenstelle` MODIFY `parent_id` integer NULL;
> ALTER TABLE `Lori_oeffnungszeiten` MODIFY `kst_id` integer NOT NULL;
> ALTER TABLE `Lori_vertragsverlauf` MODIFY `kostenstelle_id` integer NULL;
> ALTER TABLE `Lori_userkstzuordnung` MODIFY `kostenstelle_id` integer NOT
> NULL;
> ALTER TABLE `Lori_pekosollstd` MODIFY `kst_id` integer NOT NULL;
> ALTER TABLE `kostenstelle` ADD CONSTRAINT
> `kostenstelle_parent_id_d0c73a18_fk` FOREIGN KEY (`parent_id`) REFERENCES
> `kostenstelle` (`id`);
> ALTER TABLE `Lori_oeffnungszeiten` ADD CONSTRAINT
> `Lori_oeffnungszeiten_kst_id_54e15381_fk` FOREIGN KEY (`kst_id`) REFERENCES
> `kostenstelle` (`id`);
> ALTER TABLE `Lori_vertragsverlauf` ADD CONSTRAINT
> `Lori_vertragsverlauf_kostenstelle_id_59f33815_fk` FOREIGN KEY
> (`kostenstelle_id`) REFERENCES `kostenstelle` (`id`);
> ALTER TABLE `Lori_userkstzuordnung` ADD CONSTRAINT
> `Lori_userkstzuordnung_kostenstelle_id_ac2cc3c0_fk` FOREIGN KEY
> (`kostenstelle_id`) REFERENCES `kostenstelle` (`id`);
> ALTER TABLE `Lori_pekosollstd` ADD CONSTRAINT
> `Lori_pekosollstd_kst_id_6b0156f7_fk` FOREIGN KEY (`kst_id`) REFERENCES
> `kostenstelle` (`id`);
> COMMIT;
> ```
>
> My main question is:
> Why is this migration not empty, and is it safe to leave it out?
>
>
> I'm asking this because I have trouble with applying this migration.
> Apparently, not all of the previously established foreign keys are dropped
> with the upper statements and recreated with the lower statements. Error
> message of `manage.py migrate`:
> _mysql_exceptions.OperationalError: (1833, "Cannot change column 'id':
> used in a foreign key constraint
> 'Lori_kalendereintrag_kostenstelle_id_edc2995b_fk_kostenste' of table
> 'LoriDB.Lori_kalendereintrag_kstellen'")
> but this constraint is not mentioned above.
>
> Can anyone help me please?
>
> Best regards,
> Carsten
>
>
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