Nrthugu

I have a problem (at least I think). I am new in all this, so I apologize If I ask something stupid.
I have some site, which is working normally. When I try to make migrations ( python manage.py makemigrations), everything passed ok, I got the message of how many models new I have, etc. But, when I run after that migrate, I got the following output:

Operations to perform:

  Apply all migrations: admin, auth, comments, contenttypes, news, sessions

  Running migrations:

   Applying comments.0003_auto_20180816_2158...Traceback (most recent call last):

   File "../venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

  return self.cursor.execute(sql, params)

  psycopg2.ProgrammingError: syntax error at or near "WITH ORDINALITY"

  LINE 6:                     FROM unnest(c.conkey) WITH ORDINALITY co...

                                              ^





The above exception was the direct cause of the following exception:



Traceback (most recent call last):

  File "manage.py", line 15, in <module>

   execute_from_command_line(sys.argv)

  File ".../venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line

utility.execute()

 File ".../venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute

self.fetch_command(subcommand).run_from_argv(self.argv)

File ".../venv/lib/python3.6/site-packages/django/core/management/base.py", line 316, in run_from_argv

self.execute(*args, **cmd_options)

File 

  ".../venv/lib/python3.6/site-packages/django/core/management/base.py", line 353, in execute

   output = self.handle(*args, **options)

  File 

".../venv/lib/python3.6/site-packages/django/core/management/base.py", line 83, in wrapped

     res = handle_func(*args, **kwargs)

   File ".../venv/lib/python3.6/site- 

 packages/django/core/management/commands/migrate.py", line 203, in handle

fake_initial=fake_initial,

   File 





 ".../venv/lib/python3.6/site- 

packages/django/db/backends/base/schema.py", line 531, in _alter_field

fk_names = self._constraint_names(model, [old_field.column], 

foreign_key=True)

  File ".../venv/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 1027, in _constraint_names

constraints = self.connection.introspection.get_constraints(cursor, model._meta.db_table)

 File ".../venv/lib/python3.6/site- 

packages/django/db/backends/postgresql/introspection.py", line 158, in get_constraints

""", ["public", table_name])

 File ".../venv/lib/python3.6/site-packages/django/db/backends/utils.py", 

 line 100, in execute

   return super().execute(sql, params)

 File 





".../venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 68, in execute

   return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

  File ".../venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers

return executor(sql, params, many, context)

  File ".../venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

return self.cursor.execute(sql, params)

  File "/.../venv/lib/python3.6/site-packages/django/db/utils.py", line 89, in __exit__

raise dj_exc_value.with_traceback(traceback) from exc_value

  File ".../venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

  return self.cursor.execute(sql, params)

 django.db.utils.ProgrammingError: syntax error at or near "WITH 

ORDINALITY"

LINE 6:                     FROM unnest(c.conkey) WITH ORDINALITY co...

                                              ^

Anyway, if after that I try again to make migrations, got the message that I don't have migrations. So, Django did the job, But this error is here constantly when I try to migrate, I am really wondering why. I tried to google it, but I got nothing.

First, you must remove migration folders in each app

then, you can use migration commands

python manage.py makemigrations

python manage.py migrate

Whenever you are adding any new field and facing migrate error.

Kindly follow these steps:

• Delete all migration files(not the migration folder, keep the init.py file


• Truncate the _django_migrations_ table


• comment the new field which is to be added from the models.py. (Do make sure this step otherwise django will throw error when you would follow the below steps)


• run python manage.py makemigrations
  


• run python manage.py migrate --fake


• Uncomment the new field to be added


• run python manage.py makemigrations
  


• run python manage.py migrate
  

Generally these steps solve any kind of migration problem.

P.S. : When you face problem in only one app, I would recommend to delete entries of that particular app from the django_migrations table