Django 和 Postgres：持久的“ProgrammingError：列不存在”

Question

我知道之前有人在 SO 上提出过这个问题，但是我已经尝试了答案中建议的所有内容，但似乎没有任何效果。

问题：我的 Django 项目中有一个名为“Accomm”的模型类，其中存储了许多对象。在我尝试检索一个或多个“Accomm”实例的网页上，会引发以下错误...

ProgrammingError at /
column objects_accomm.description does not exist
LINE 1: ...omm"."id", "objects_accomm"."mapped_location_id", "objects_a...

当我将新字段“description”迁移到“Accomm”模型时，开始出现此问题。

尝试过的解决方案：我尝试做以下事情...清除所有 Django 迁移（使用 --zero 和 --empty 命令）；清除数据库（PostgreSQL 10）；清除迁移和数据库；在 Django 项目 settings.py 文件中更改我的数据库的名称。这些似乎都不起作用。我也跟着教程here、here和here。

完全错误：

Django Version: 1.11.7
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.gis',
 'django.contrib.humanize',
 'django.contrib.messages',
 'django.contrib.sessions',
 'django.contrib.staticfiles',
 'rest_framework',
 'accounts',
 'maps',
 'objects',
 'social_django']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'social_django.middleware.SocialAuthExceptionMiddleware']

Traceback:

    File "/Library/Python/2.7/site-packages/django/core/handlers/exception.py" in inner
      41.             response = get_response(request)

    File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in _get_response
      187.                 response = self.process_exception_by_middleware(e, request)

    File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in _get_response
      185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

    File "/Users/jayt/project/main/views.py" in home
      21.     return render(request, 'home.html', {'accomm':accomm})

    File "/Library/Python/2.7/site-packages/django/shortcuts.py" in render
      30.     content = loader.render_to_string(template_name, context, request, using=using)

    File "/Library/Python/2.7/site-packages/django/template/loader.py" in render_to_string
      68.     return template.render(context, request)

    File "/Library/Python/2.7/site-packages/django/template/backends/django.py" in render
      66.             return self.template.render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render
      207.                     return self._render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in _render
      199.         return self.nodelist.render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render
      990.                 bit = node.render_annotated(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
      957.             return self.render(context)

    File "/Library/Python/2.7/site-packages/django/template/loader_tags.py" in render
      177.             return compiled_parent._render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in _render
      199.         return self.nodelist.render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render
      990.                 bit = node.render_annotated(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
      957.             return self.render(context)

    File "/Library/Python/2.7/site-packages/django/template/loader_tags.py" in render
      72.                 result = block.nodelist.render(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render
      990.                 bit = node.render_annotated(context)

    File "/Library/Python/2.7/site-packages/django/template/base.py" in render_annotated
      957.             return self.render(context)

    File "/Library/Python/2.7/site-packages/django/template/defaulttags.py" in render
      321.             if match:

    File "/Library/Python/2.7/site-packages/django/db/models/query.py" in __nonzero__
      258.         return type(self).__bool__(self)

    File "/Library/Python/2.7/site-packages/django/db/models/query.py" in __bool__
      254.         self._fetch_all()

    File "/Library/Python/2.7/site-packages/django/db/models/query.py" in _fetch_all
      1118.             self._result_cache = list(self._iterable_class(self))

    File "/Library/Python/2.7/site-packages/django/db/models/query.py" in __iter__
      53.         results = compiler.execute_sql(chunked_fetch=self.chunked_fetch)

    File "/Library/Python/2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
      894.             raise original_exception

    Exception Type: ProgrammingError at /
    Exception Value: column objects_accomm.description does not exist
    LINE 1: ...omm"."id", "objects_accomm"."mapped_location_id", "objects_a...
                                                             ^

编辑： “Accomm”的 Models.py：

class Accomm(models.Model):
    mapped_location=models.ForeignKey(Location,related_name='l_accomms',null=True,blank=True,on_delete=models.SET_NULL)
    description=models.CharField(max_length=1000,null=True,blank=True)
    creator=models.OneToOneField(accountmodels.UserProfileModel,related_name='u_creator',null=True,on_delete=models.SET_NULL,blank=True)
    slug_key=models.SlugField(unique=True)
    is_active=models.BooleanField(default=False)

Views.py：

def home(request):
    user = request.user
    accomm = Accomm.objects.annotate(img_count=models.Count('a_image')).filter(img_count__gte=1)[:6]
    return render(request, 'home.html', {'accomm':accomm})

除了这里提出的解决方案还有什么其他想法吗？

Answer 1

当我的迁移变得不稳定时，我喜欢尝试如下：

python manage.py makemigrations
python manage.py migrate --fake

所以这会让你的模型看起来像是添加了列，所以我从这里剪切模型并将其粘贴到一个临时文件中，保存模型并定期运行迁移，这将删除所有模型。然后将模型粘贴回 models.py 并再次运行迁移。这似乎对我有用，可能有更好的方法来管理它，但是我对 django 比较陌生，因为我刚刚完成了我的第一个大项目。真的希望这会有所帮助，如果不让我知道，我可能还有其他东西要给你！