Django数据库工具包出现错误：relation "django_content_type" does not exist。

Question

我有一个在我的电脑上缓慢构建起来的项目，它正常运行。现在我想将它放到服务器上，但我遇到了以下错误：

django.db.utils.ProgrammingError: relation "django_content_type" does not exist

我无法找出问题所在，Stackoverflow上的帖子建议删除迁移并重新创建，但我已经尝试过却仍然存在相同的问题。如果您能指导我应该查找什么，我将不胜感激。

下面是错误追溯：

Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
    utility.execute()
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/__init__.py", line 365, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/base.py", line 332, in execute
    self.check()
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/base.py", line 364, in check
    include_deployment_checks=include_deployment_checks,
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 58, in _run_checks
    issues.extend(super()._run_checks(**kwargs))
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/management/base.py", line 351, in _run_checks
    return checks.run_checks(**kwargs)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/checks/registry.py", line 73, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
    all_namespaces = _load_all_namespaces(resolver)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
    url_patterns = getattr(resolver, 'url_patterns', [])
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/utils/functional.py", line 36, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/urls/resolvers.py", line 540, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/utils/functional.py", line 36, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/urls/resolvers.py", line 533, in urlconf_module
    return import_module(self.urlconf_name)
  File "/var/www/jobsite/env/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 "/var/www/jobsite/jobsite/urls.py", line 32, in <module>
    path('', include('user_management.urls')),
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/urls/conf.py", line 34, in include
    urlconf_module = import_module(urlconf_module)
  File "/var/www/jobsite/env/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 "/var/www/jobsite/user_management/urls.py", line 3, in <module>
    from user_management import views
  File "/var/www/jobsite/user_management/views.py", line 11, in <module>
    from user_management.forms import ApplicantSignUpForm, CompanySignUpForm, CompanyUserSignUpForm, ApplicationForm
  File "/var/www/jobsite/user_management/forms.py", line 82, in <module>
    class ApplicationForm(forms.ModelForm):
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/forms/models.py", line 256, in __new__
    apply_limit_choices_to=False,
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/forms/models.py", line 172, in fields_for_model
    formfield = f.formfield(**kwargs)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/fields/related.py", line 953, in formfield
    'queryset': self.remote_field.model._default_manager.using(using),
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/secretballot/__init__.py", line 59, in get_queryset
    content_type = ContentType.objects.get_for_model(self.model).id
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/contrib/contenttypes/models.py", line 51, in get_for_model
    ct = self.get(app_label=opts.app_label, model=opts.model_name)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/query.py", line 397, in get
    num = len(clone)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/query.py", line 254, in __len__
    self._fetch_all()
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/query.py", line 1179, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/query.py", line 53, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/models/sql/compiler.py", line 1068, in execute_sql
    cursor.execute(sql, params)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/backends/utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/var/www/jobsite/env/lib/python3.5/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: relation "django_content_type" does not exist
LINE 1: ..."."app_label", "django_content_type"."model" FROM "django_co...

编辑 添加了申请表

class ApplicationForm(forms.ModelForm):
    class Meta:
        model = Application
        exclude = ['applied_at']

        widgets = {
            'job' : forms.HiddenInput(),
            'user' : forms.HiddenInput(),
            'apply_name' :forms.TextInput(attrs={ "class" : 'form-control'}),
            'apply_email' : forms.EmailInput(attrs={ "class" : 'form-control'}),
            'apply_cv' : forms.FileInput(attrs={'class' : 'form-control', 
                                            'id' : 'input-file'}),
            'ip_address' : forms.HiddenInput()
        }

- HenryM

---

回溯信息显示错误发生在“class ApplicationForm”中，请在您的问题中包含此信息。 - Alasdair

删除迁移是一项激烈的措施，通常只有在您愿意删除数据库并重新开始时才应该这样做。 - Alasdair

我知道删除迁移文件可能有些激进（我已经备份了它们），但我正在为这个问题苦苦挣扎。 - HenryM

第一次迁移时是否发生了这种情况？如果是的话，这里有一个可能不太靠谱的解决方法：在您的 urls.py 文件中（看起来您有一个），将 url_patterns = [...] 放在 try-Except 结构内，并在 Exception 部分设置 urlpatterns=[]。您的错误可能是因为代码尝试处理尚未设置的数据库而导致的。 - Alain

很好，你备份了迁移。我见过许多用户在没有备份的情况下删除它们，因此我认为任何建议在没有警告的情况下删除它们的答案都是不负责任的。 - Alasdair

Answer 1

阿兰解决了这个问题。

这发生在第一个迁移中。

问题出现在urls.py文件中。

将你的url_patterns=[...]语句放在一个try-Except结构中，并在异常部分设置urlpatterns=[]。你的错误可能是由于代码尝试使用尚未设置的数据库而导致的。

- HenryM

---

类似这里，但我是在views.py的顶层范围中导入和使用ContentTypes（由urls.py运行）。我通过在视图内更深层次地导入和使用内容类型来解决了我的问题，因此它不会在评估urls.py时运行。 - Harry Moreno