Django Programming error column does not exist even after running migrations

Question

I run python manage.py makemigrations and I get: No changes detected Then, python manage.py migrate and I get: No migrations to apply.

Answer 1

The issue was in the Models for me, for some reason Django was adding '_id' to the end of my Foreign Key column. I had to explicitly set the related named to the Foreign Key. Here 'Cards' is the parent table and 'Prices' is the child table.

class Cards(models.Model):
    unique_id = models.CharField(primary_key=True, max_length=45)
    name = models.CharField(max_length=225)   

class Prices(models.Model):
        unique_id = models.ForeignKey(Cards, models.DO_NOTHING)

Works after changing to:

class Cards(models.Model):
    unique_id = models.CharField(primary_key=True, max_length=45)
    name = models.CharField(max_length=225)   

class Prices(models.Model):
        unique_id = models.ForeignKey(Cards, models.DO_NOTHING, db_column='unique_id')

Answer 2

I got the same problem (column not exist) but when I try to run migrate not with makemigrations (it is the same issue I believe)

• Cause: I removed the migration files and replaced them with single pretending intial migration file 0001 before running the migration for the last change

• Solution:

  1. Drop tables involved in that migration of that app (consider a backup workaround if any)
  2. Delete the rows responsible of the migration of that app from the table django_migrations in which migrations are recorded, This is how Django knows which migrations have been applied and which still need to be applied.

And here is how solve this problem:

• log in as postgres user (my user is called posgres):

  sudo -i -u postgres

• Open an sql terminal and connect to your database:

  psql -d database_name

• List your table and spot the tables related to that app:

  \dt

• Drop them (consider drop order with relations):

  DROP TABLE tablename ;

• List migration record, you will see migrations applied classified like so:

id | app | name | applied
--+------+--------+---------+

SELECT * FROM django_migrations;

• Delete rows of migrations of that app (you can delete by id or by app, with app don't forget 'quotes'):

  DELETE FROM django_migrations WHERE app='yourapp';

• log out and run your migrations merely (maybe run makemigrations in your case):

  python manage.py migrate --settings=your.settings.module_if_any

Note: it is possible that in your case will not have to drop all the tables of that app and not all the migrations, just the ones of the models causing the problem.

I wish this can help.

Answer 3

Here's what i tried and it worked:

• Go and add manually the column to your table
• run python manage.py makemigrations
• go back drop that column you added
• run python manage.py migrate

Answer 4

Just remove corresponding row migrations for that model in 'django_migrations' model in database.

And re run python manage.py migrate app_name

Answer 5

I had a similar issue - the error message appeared when I clicked on the model on the django-admin site. I solved it by commenting out the field in models.py, then running migrations. Following this I uncommented the field and re ran the migrations. After that the error message disappeared.

Answer 6

My case might be a bit obscure, but if it helps someone, it is worth documenting here.

I was calling a function in one of my migrations, which imported a Model of said migration regularly, i.e.

from myApp.models import ModelX

The only way models should be imported in migrations would be using e.g. RunPython:

def myFunc(apps, schema_editor): 
    MyModel = apps.get_model('myApp 'MyModel')

and then calling that function like so:

class Migration(migrations.Migration):
    operations = [
        migrations.RunPython(initialize_mhs, reverse_code=migrations.RunPython.noop),
    ]

Additionally the original import worked until I modified the model in a later migration, making this error harder to locate.