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

问题:

After I install Django-userena,there is an error my django version :1.9.5 I just install django-userena step by step ,but when i migrate it ,an error happend and I don't how to solve it.

    Traceback (most recent call last):
  File "manage.py", line 12, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Python27\lib\site-packages\django\core\management\base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Python27\lib\site-packages\django\core\management\base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "C:\Python27\lib\site-packages\django\core\management\commands\migrate.py", line 204, in handle
    emit_post_migrate_signal(self.verbosity, self.interactive, connection.alias)
  File "C:\Python27\lib\site-packages\django\core\management\sql.py", line 50, in emit_post_migrate_signal
    using=db)
  File "C:\Python27\lib\site-packages\django\dispatch\dispatcher.py", line 192, in send
    response = receiver(signal=self, sender=sender, **named)
  File "C:\Python27\lib\site-packages\guardian\management\__init__.py", line 33, in create_anonymous_user
    User.objects.get(**lookup)
  File "C:\Python27\lib\site-packages\django\db\models\manager.py", line 122, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Python27\lib\site-packages\django\db\models\query.py", line 381, in get
    num = len(clone)
  File "C:\Python27\lib\site-packages\django\db\models\query.py", line 240, in __len__
    self._fetch_all()
  File "C:\Python27\lib\site-packages\django\db\models\query.py", line 1074, in _fetch_all
    self._result_cache = list(self.iterator())
  File "C:\Python27\lib\site-packages\django\db\models\query.py", line 52, in __iter__
    results = compiler.execute_sql()
  File "C:\Python27\lib\site-packages\django\db\models\sql\compiler.py", line 848, in execute_sql
    cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\base.py", line 323, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: auth_user

apps:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.contrib.sites',

    'userena',
    'guardian',
    'easy_thumbnails',
    'accounts',    
]

回答1:

The problem is this line:

File "C:\Python27\lib\site-packages\guardian\management\__init__.py", line 33, in create_anonymous_user User.objects.get(**lookup)

guardian\management\__init__.py is calling User before it is defined.

Why is it called before it is defined? ...well, it is called by makemigrations to find out if there are changes in the db to define them (the changes that are found)

...so this is a "chicken and egg" problem.

I have the same error with a similar problem but the offending code was my own code (not a library like guardian)

My code was like this:

CHAT_BOT_USER, created = User.objects.get_or_create(username='rosty', \ email=settings.EMAIL_HOST_USER)

The offending part is the User being used before the auth_user table is created

I solved by only executing the code when the table is present. This happens when there is no OperationError. And you can know it with a try/except like this:

from django.db import OperationalError

try:
    CHAT_BOT_USER, created = User.objects.get_or_create(username='rosty', email=settings.EMAIL_HOST_USER)

except OperationalError:
    CHAT_BOT_USER = None

if created:
    CHAT_BOT_USER.set_password(settings.EMAIL_HOST_PASSWORD)
    CHAT_BOT_USER.save()

This way makemigrations runs the except code and runserver runs the try code.

Note the created boolean, you may use any other way to avoid makemigration run code that depends on the User.objects.... results

回答2:

./manage.py migrate

if your Django version is 1.9 or lower, use

./manage.py syncdb

then

python manage.py createsuperuser

more details on https://github.com/django/django/blob/master/django/contrib/auth/forms.py

May it help

回答3:

I was get same error and to fix the same, I checked if the mentioned table in error is present in connected DB or not. It was not. Applied migration again and it worked.

python manage.py migrate

python manage.py makemigrations