CODEWITHSUNDEEP
django
kikee1222
kikee1222

Reputation: 2036

Getting django model errors for a model I am trying to delete

Can you help?

I made a mistake on my Django models.py and wanted to then delete the model.

As you can see from the below, the migration was to delete the model called code.

However, it still errors & doesn't delete the model.

What can I do?

root@new:/home/django/django_project# python manage.py makemigrations
Migrations for 'netshock':
  netshock/migrations/0018_delete_code.py
    - Delete model code
root@new:/home/django/django_project# python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, netshock, sessions
Running migrations:
  Applying netshock.0012_code...Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/lib/python2.7/dist-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python2.7/dist-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python2.7/dist-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/lib/python2.7/dist-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 204, in handle
    fake_initial=fake_initial,
  File "/usr/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 115, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/usr/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/lib/python2.7/dist-packages/django/db/migrations/operations/models.py", line 97, in database_forwards
    schema_editor.create_model(model)
  File "/usr/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 303, in create_model
    self.execute(sql, params or None)
  File "/usr/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 120, in execute
    cursor.execute(sql, params)
  File "/usr/lib/python2.7/dist-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/lib/python2.7/dist-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/lib/python2.7/dist-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
django.db.utils.ProgrammingError: syntax error at or near "4000000000"
LINE 1: ...("id" serial NOT NULL PRIMARY KEY, "code" varchar(4000000000...

Upvotes: 1

Views: 64

Answers (1)

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 477686

The problem is specified at the bottom of the error:

django.db.utils.ProgrammingError: syntax error at or near "4000000000"
LINE 1: ...("id" serial NOT NULL PRIMARY KEY, "code" varchar(4000000000...

Now 4000000000 is simply too large. PostgreSQL mentions that the maximum size of character types is 1GB [PostgreSQL-doc]:

(...) In any case, the longest possible character string that can be stored is about 1 GB. (The maximum value that will be allowed for n in the data type declaration is less than that. It wouldn't be useful to change this because with multibyte character encodings the number of characters and bytes can be quite different. If you desire to store long strings with no specific upper limit, use text or character varying without a length specifier, rather than making up an arbitrary length limit.)

So setting this to 4'000'000'000 makes no sense.

If you later make extra changes, this will not resolve the issue (at least not immediately), since you created migration files with the 4000000000 in these. You will have to remove the migration files that can not be applied (together with the ones that follow on these migrations, since otherwise there is likely an error in the chain), and make new migration files.

Upvotes: 1

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