django.db.utils.OperationalError 无论我尝试什么答案

【问题标题】：django.db.utils.OperationalError no matter what I trydjango.db.utils.OperationalError 无论我尝试什么
【发布时间】：2016-11-28 14:59:08
【问题描述】：

好吧，我被难住了。我想我什么都试过了。

我在应用程序的models.py 中创建了一个模型，并且还在现有模型中添加了更多字段（所有字段都具有默认值）。然后我跑了makemigrations。结果：

$ python3 manage.py makemigrations
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/sqlite3/base.py", line 323, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such column: myapp_MyExistingModel.first_new_field

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

Traceback (most recent call last):
  File "manage.py", line 14, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 398, in execute
    self.check()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 426, in check
    include_deployment_checks=include_deployment_checks,
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/registry.py", line 75, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 13, in check_url_config
    return check_resolver(resolver)
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 23, in check_resolver
    for pattern in resolver.url_patterns:
  File "/usr/local/lib/python3.5/dist-packages/django/utils/functional.py", line 33, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/local/lib/python3.5/dist-packages/django/core/urlresolvers.py", line 417, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/functional.py", line 33, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/local/lib/python3.5/dist-packages/django/core/urlresolvers.py", line 410, in urlconf_module
    return import_module(self.urlconf_name)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/path/to/myproject/myproject/urls.py", line 49, in <module>
    url(r'^someurl/', include('myapp.urls')),
  File "/usr/local/lib/python3.5/dist-packages/django/conf/urls/__init__.py", line 52, in include
    urlconf_module = import_module(urlconf_module)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/path/to/myproject/myapp/urls.py", line 2, in <module>
    from . import views
  File "/path/to/myproject/myapp/views.py", line 8, in <module>
    existing_model = MyExistingModel.objects.all()[0]
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 297, in __getitem__
    return list(qs)[0]
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 258, in __iter__
    self._fetch_all()
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 1074, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 52, in __iter__
    results = compiler.execute_sql()
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/compiler.py", line 848, in execute_sql
    cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/sqlite3/base.py", line 323, in execute
        return Database.Cursor.execute(self, query, params)
    django.db.utils.OperationalError: no such column: myapp_MyExistingModel.first_new_field

如果重要的话，我使用的是 Mezzanine CMS，而 MyExistingModel 是其 Page 类的扩展。它只有一个实例。

这就是我接下来尝试的：

manage.py migrate --fake
manage.py flush
重命名我的数据库，以便创建一个新数据库

所有这些都抛出了相同的回溯。我进入了应用程序的最后一次迁移。它包含一个AddModel 用于我的新模型，RemoveField 用于我重命名的旧模型中的一个字段，但没有AddField 用于我创建的新字段。所以我手动将它们添加到迁移文件中并重试manage.py migrate --fake。相同的追溯。我也尝试了所有其他命令。相同的追溯。

最后，我删除了所有应用的迁移，只留下了__init__.py。我还重命名了数据库，以便重新创建它。我重试了flush、makemigrations 和migrate（有和没有--fake）。所有这些都导致了这个回溯：

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/sqlite3/base.py", line 323, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: myapp_MyExistingModel

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

Traceback (most recent call last):
  File "manage.py", line 14, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 398, in execute
    self.check()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 426, in check
    include_deployment_checks=include_deployment_checks,
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/registry.py", line 75, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 13, in check_url_config
    return check_resolver(resolver)
  File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 23, in check_resolver
    for pattern in resolver.url_patterns:
  File "/usr/local/lib/python3.5/dist-packages/django/utils/functional.py", line 33, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/local/lib/python3.5/dist-packages/django/core/urlresolvers.py", line 417, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/functional.py", line 33, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/local/lib/python3.5/dist-packages/django/core/urlresolvers.py", line 410, in urlconf_module
    return import_module(self.urlconf_name)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/path/to/myproject/myproject/urls.py", line 49, in <module>
    url(r'^someurl/', include('myapp.urls')),
  File "/usr/local/lib/python3.5/dist-packages/django/conf/urls/__init__.py", line 52, in include
    urlconf_module = import_module(urlconf_module)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/path/to/myproject/myapp/urls.py", line 2, in <module>
    from . import views
  File "/path/to/myproject/myapp/views.py", line 8, in <module>
    existing_model = MyExistingModel.objects.all()[0]
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 297, in __getitem__
    return list(qs)[0]
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 258, in __iter__
    self._fetch_all()
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 1074, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 52, in __iter__
    results = compiler.execute_sql()
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/compiler.py", line 848, in execute_sql
    cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-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: myapp_MyExistingModel

在这一点上，我不知道接下来要尝试什么，除了start over。任何建议表示赞赏。

【问题讨论】：

为什么要迁移 --fake？这将导致未创建表，这可能就是您看到此问题的原因
这是上次我在数据库和迁移之间出现不一致时拯救我的魔术。我不认为migrate 可以在makemigrations 之前工作，除非在手动编辑迁移文件之后。我只是在这样做之后尝试了migrate 没有--fake，但这也不起作用。我将编辑问题以反映这一点。
这就是伪装救了我的地方：groups.google.com/d/msg/mezzanine-users/wp7TAK2L_Dg/…

标签： python django python-3.x django-models mezzanine

【解决方案1】：

我想通了！经验教训：阅读整个堆栈跟踪，而不仅仅是最后一行。在这种情况下，进攻线在我的views.py：

File "/path/to/myproject/myapp/views.py", line 8, in <module>
  existing_model = MyExistingModel.objects.all()[0]

就像我说的，MyExistingModel 只有一个实例，这一行将该实例设置为局部变量 existing_model 以在 views.py 代码中使用。

我仍然不明白为什么 makemigrations 需要运行 views.py。但它确实如此，显然！在此过程中，MyExistingModel 是从 models.py 导入的，包括新字段。但是这些字段还没有被迁移。因此，操作错误。

【讨论】：

“非常感谢您的评论” - 我建议您打开一个新问题，因为 cmets 不适用于扩展讨论。
确实如此。好的，我将讨论移至this post on reddit。