postgresql - Django Migration Error: Column does not exist

Question

Python 3, Django 1.8.5, Postgres

I have a model Sites that has been working fine. I recently tried to add a field, airport_code, and migrate the data.

class Site(BaseModel):

  objects = SiteManager()

  name = models.CharField(max_length=200, unique=True)
  domain = models.CharField(max_length=200, unique=True)
  weather = models.CharField(max_length=10)
  nearby_sites = models.ManyToManyField('self', symmetrical=False, blank=True)
  users = models.ManyToManyField(settings.AUTH_USER_MODEL, blank=True)
  facebook = models.URLField(max_length=200)
  twitter = models.URLField(max_length=200)
  header_override = models.TextField(blank=True)
  email_header_override = models.TextField(blank=True)
  timely_site_tag_id = models.IntegerField()
  timely_featured_tag_id = models.IntegerField()
  timely_domain = models.CharField(max_length=255)
  sitemap_public_id = models.CharField(max_length=255)
  state = models.CharField(max_length=24)
  airport_code = JSONField()

However, when I ran makemigrations I got an error:

django.db.utils.ProgrammingError: column sites_site.airport_code does not exist LINE 1: ..._site"."sitemap_public_id", "sites_site"."state", "sites_sit...

Of course, this doesn't make sense, because the column obviously does not exist when I'm trying to create it within the migration.

I have seen many questions about this bug on Stack Overflow that are unanswered, or have a solution to manually create the migration file, or destroy and rebuild the database. This is not an okay solution.

Answer 1

After you run makemigrations, be sure to go through the stack trace step by step.

In my case, I noticed it traced through a call to a Form contained within a forms.py in a completely different app, which happened to have a call to the model I was trying to create a new migration for.

Moving the Form class out of forms.py into the views.py fixed the issue.