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python之django.db.utils.OperationalError 无论我尝试什么

2024年10月17日20kerrycode

好吧，我被难住了。我想我已经尝试了一切。

我在应用程序的 models.py 中创建了一个模型，并向现有模型添加了更多字段(均具有默认值)。然后我运行了 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。

所以这是我接下来尝试的:

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

所有这些都抛出相同的回溯。我进入了该应用程序的最后一次迁移。它包含一个用于我的新模型的 AddModel 和一个用于我重命名的旧模型中的字段的 RemoveField，但没有用于我重命名的新字段的 AddField创建。所以我手动将它们添加到迁移文件并重试 manage.py migrate --fake。相同的回溯。我也尝试了所有其他命令。相同的回溯。

最后，我删除了所有应用程序的迁移，只留下 __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(使用和不使用 --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

此时，除了start over，我什至不知道下一步该尝试什么.任何建议表示赞赏。

请您参考如下方法:

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，攻击线在我的 views.py 中。 :

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用于 views.py代码。

我还是不明白为什么makemigrations需要运行 views.py .但它确实如此，显然!这样做，MyExistingModel从 models.py 导入, 包括 新字段。但这些字段尚未迁移。因此，操作错误。


  文章来源：
  https://blog.windname.com/post/ifeab2b9.html
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