Table not found in migration file

Question

Error Message

django.db.utils.OperationalError: no such table: clientauth_tbltokentypes

What I am trying to do

I am trying to migrate data with table generation.

models.py

class tbltokentypes(models.Model):
    token_type_id: AutoField(primary_key=True)
    token_type: CharField(max_length=30)

I ran the command python manage.py makemigrations, which created the file 0001_initial.py.

Then in the migration file, I added managers:

from django.db import migrations, models
from clientauth.models import tbltokentypes

class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='tbltokentypes',
            fields=[
                ('token_type_id', models.AutoField(primary_key=True, serialize=False, verbose_name='token_type_id')),
                ('token_type', models.CharField(max_length=30)),
            ],
            managers=[
                tbltokentypes(token_type = "Registration").save()
            ]
        )
    ]

Am I missing anything?

score 1 · Accepted Answer · answered Sep 27 '21 at 17:14

Wrap your function call in migrations.RunPython, otherwise it will be run while assigning operations, before the migration can even be run to create your table.

from django.db import migrations, models
# from clientauth.models import tbltokentypes  # Remove this


# Add this function
def migrate_tbltokentypes(apps, schema_editor):
    # We can't import the Person model directly as it may be a newer
    # version than this migration expects. We use the historical version.
    tbltokentypes = apps.get_model('clientauth', 'tbltokentypes')
    tbltokentypes(token_type="Registration").save()


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='tbltokentypes',
            fields=[
                ('token_type_id', models.AutoField(primary_key=True, serialize=False)),
                ('token_type', models.CharField(max_length=30)),
            ],
            # managers=[                                             # Change this
            #     tbltokentypes(token_type = "Registration").save()  #
            # ]                                                      #
        ),
        migrations.RunPython(migrate_tbltokentypes),                 # to this
    ]

Also note, from https://docs.djangoproject.com/en/3.2/topics/migrations/#data-migrations:

[Data migrations are] best written as separate migrations, sitting alongside your schema migrations.

python manage.py makemigrations --empty clientauth --name migrate_tbltokentypes

Yes, inside the migration file. You want it as part of the migration right? You're not supposed to remove migrations, though if you write data migrations as separate migrations, then you can move the files before rebuilding migrations -- but then the data migration would be redundant since there would be no data. Do you actually want to seed data instead, based on the latest schema (separate from migrations)? If so, look at `loaddata` command ([docs.djangoproject.com/en/3.2/ref/django-admin/#django-admin-loaddata](https://docs.djangoproject.com/en/3.2/ref/django-admin/#django-admin-loaddata)). — aaron, Sep 28 '21 at 01:20
There will be a risk writing code in auto generated migration file which can be replaced accidently whenever running `python manage.py makemigrations`. right? I meant, can I put the data migration code somewhere else to avoid this problem. — Pankaj, Sep 28 '21 at 03:12
Running `python manage.py makemigrations` will not replace migrations. — aaron, Sep 28 '21 at 04:15

Table not found in migration file

Error Message

What I am trying to do

models.py

1 Answers1