我真是一筹莫及。经过十几个小时的故障排除，可能更多，我以为我终于可以做生意了，但接着我发现:
Model class django.contrib.contenttypes.models.ContentType doesn't declare an explicit app_label
网上关于这方面的信息太少了，没有解决方案可以解决我的问题。任何建议都将不胜感激。
我使用的是Python 3.4和Django 1.10。
从我的settings.py:
INSTALLED_APPS = [
'DeleteNote.apps.DeletenoteConfig',
'LibrarySync.apps.LibrarysyncConfig',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
]
我的app .py文件是这样的:
from django.apps import AppConfig
class DeletenoteConfig(AppConfig):
name = 'DeleteNote'
and
from django.apps import AppConfig
class LibrarysyncConfig(AppConfig):
name = 'LibrarySync'
我只是遇到了这个问题，并找出了哪里出了问题。由于之前的回答没有描述这个问题发生在我身上，我想我可以把它发布给其他人:
the issue came from using python migrate.py startapp myApp from my project root folder, then move myApp to a child folder with mv myApp myFolderWithApps/.
I wrote myApp.models and ran python migrate.py makemigrations. All went well.
then I did the same with another app that was importing models from myApp. Kaboom! I ran into this error, while performing makemigrations. That was because I had to use myFolderWithApps.myApp to reference my app, but I had forgotten to update MyApp/apps.py. So I corrected myApp/apps.py, settings/INSTALLED_APPS and my import path in my second app.
but then the error kept happening: the reason was that I had migrations trying to import the models from myApp with the wrong path. I tried to correct the migration file, but I went at the point where it was easier to reset the DB and delete the migrations to start from scratch.
长话短说:
-这个问题最初是来自myApp的apps.py中的应用程序名称错误，在设置和我的第二个应用程序的导入路径。
-但仅仅纠正这三个地方的路径是不够的，因为导入时引用了错误的应用程序名称。因此，同样的错误在迁移过程中不断发生(除了这次是从迁移中)。
所以…检查您的迁移，祝您好运!
在我的例子中，我在将代码从Django 1.11.11移植到Django 2.2时得到了这个错误。我正在定义一个自定义的FileSystemStorage派生类。在Django 1.11.11中，我在models.py中有如下一行:
from django.core.files.storage import Storage, DefaultStorage
然后在文件中我有类定义:
class MyFileStorage(FileSystemStorage):
然而，在Django 2.2中，我需要在导入时显式引用FileSystemStorage类:
from django.core.files.storage import Storage, DefaultStorage, FileSystemStorage
瞧!，错误消失。
注意，每个人都在报告Django服务器吐出的错误消息的最后一部分。然而，如果你向上滚动，你会在错误的中间找到原因。
在我的例子中，在settings.py中的BASE_DIR有一个问题。这是包的结构:
project_root_directory
└── service_package
└── db_package
├── my_django_package
│ └── my_django_package
│ ├── settings.py
│ └── ...
└── my_django_app
├── migrations
├── models.py
└── ...
它在更新settings.py时工作:
INSTALLED_APPS = [
'some_django_stuff_here...',
'some_django_stuff_here....',
...
'service_package.db_package.my_django_app'
]
BASE_DIR指向项目根目录
BASE_DIR = Path(__file__).resolve().parent.parent.parent.parent.parent
在调试中运行django，在registry.py中使用断点-> def get_containing_app_config(self, object_name)
