OperationalError：没有这样的表：使用unittest时的django_content_type

Question

我正在尝试为我的 django 项目启动 unittest，但它返回以下错误：

ERROR: varys.users.tests.test_all_views (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
ImportError: Failed to import test module: varys.users.tests.test_all_views
Traceback (most recent call last):
  File "/usr/lib/python2.7/unittest/loader.py", line 254, in _find_tests
    module = self._get_module_from_name(name)
  File "/usr/lib/python2.7/unittest/loader.py", line 232, in _get_module_from_name
    __import__(name)
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/users/tests/__init__.py", line 1, in <module>
    from .test_all_views import *
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/users/tests/test_all_views.py", line 12, in <module>
    from ...urls import urlpatterns
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/urls.py", line 18, in <module>
    url(r'^survey/', include('varys.surveys.urls')),
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/conf/urls/__init__.py", line 26, in include
    urlconf_module = import_module(urlconf_module)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/surveys/urls.py", line 13, in <module>
    from .userrankingreview.views import UserRankingReviewView
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/surveys/userrankingreview/views.py", line 6, in <module>
    from .forms import UserRankingReviewFormset
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/surveys/userrankingreview/forms.py", line 63, in <module>
    formfield_callback=formfield_callback
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/forms/models.py", line 981, in inlineformset_factory
    FormSet = modelformset_factory(model, **kwargs)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/forms/models.py", line 813, in modelformset_factory
    labels=labels, help_texts=help_texts, error_messages=error_messages)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/forms/models.py", line 528, in modelform_factory
    return type(form)(class_name, (form,), form_class_attrs)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/forms/models.py", line 282, in __new__
    opts.help_texts, opts.error_messages)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/forms/models.py", line 205, in fields_for_model
    formfield = formfield_callback(f, **kwargs)
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/surveys/userrankingreview/forms.py", line 54, in formfield_callback
    return field.formfield()
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/fields/related.py", line 1263, in formfield
    'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to),
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/manager.py", line 226, in using
    return self.get_queryset().using(*args, **kwargs)
  File "/home/antonscherbatov/projects/varys/locus-web-varys-d/varys/surveys/models.py", line 199, in get_query_set
    qs = qs.filter(**self.model.subclasses_lookup())
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/polymodels/models.py", line 59, in subclasses_lookup
    query_name=query_name
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/polymodels/models.py", line 50, in content_type_lookup
    value = [ct.pk for ct in get_content_types(models).values()]
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/polymodels/utils.py", line 26, in get_content_types
    return manager.get_for_models(*models, for_concrete_models=False)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/contrib/contenttypes/models.py", line 79, in get_for_models
    for ct in cts:
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/query.py", line 96, in __iter__
    self._fetch_all()
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/query.py", line 857, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/query.py", line 220, in iterator
    for row in compiler.results_iter():
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 713, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 786, in execute_sql
    cursor.execute(sql, params)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/utils.py", line 99, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)
  File "/home/antonscherbatov/projects/varys/ve/local/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 451, in execute
    return Database.Cursor.execute(self, query, params)
OperationalError: no such table: django_content_type

昨天所有测试都运行良好。检查后我注意到问题出在下面的代码中

# forms.py

UserRankingReviewFormset = inlineformset_factory(
    UserRankingReviewRequest,
    UserRankingReview,
    formset=UserRankingInlineFormSet,
    extra=0,
    can_delete=False,
    formfield_callback=formfield_callback
)

其中 parent_model UserRankingReviewRequest 是代理模型，而 UserRankingReview 模型对 UserRankingReviewRequest 有外键“请求”。

当我为此模型设置标志 Proxy = False 时，测试运行良好，但我只需要将此模型作为代理

有什么办法可以防止这种情况发生吗？

Answer 1

Proxy = True

表示没有为模型创建实际的数据库表。因此，当您尝试使用 ForeignKey 引用模型时，事情就会中断（因为 ForeignKey 没有可指向的 db 表）。

如果您想要实现的是拥有一个具有具体子类型的“通用抽象”类型对象，并且想要任何子类型的外键，我建议您查看https://docs.djangoproject.com/en/1.8/ref/contrib/contenttypes/#generic-relations（使用自定义将 ForeignKey 上的 limit_choices_to 设置为 ContentType https://docs.djangoproject.com/en/1.8/ref/models/fields/#django.db.models.ForeignKey.limit_choices_to)

您可能还对 Django Polymorphic (https://django-polymorphic.readthedocs.org/en/latest/) 感兴趣，它可以完成所有这些以及更多功能。

Answer 2

如果这发生在测试中，就像对我一样， 也许this链接 可以帮忙，简而言之，答案是：

好的，我找到了解决问题的方法，以防万一有人遇到同样的问题 问题。如果您在设置中指定TEST_DATABASE_NAME，它将 强制 sqllite 使用文件数据库而不是内存数据库， 然后问题就来了。