Django - 为什么我在使用 shell 时会收到 OperationalError（仅）？

Question

我遇到了一个奇怪的情况。怎么了？

当我从项目目录运行python manage.py shell，导入一个模型（任何模型），并尝试访问它的Model.objects（objects.all()，objects.create()，...），它会抛出一个OperationalError如下引用。

>>> from Interface.models import ClientUser
>>> ClientUser.objects.all()

django.db.utils.OperationalError：没有这样的表：Interface_clientuser

>>> ClientUser.objects.create()

django.db.utils.OperationalError：没有这样的表：Interface_clientuser

我试过删除数据库然后运行python manage.py migrate，关闭所有东西并重新启动我的电脑，然后非常努力地盯着代码（大声笑），但无济于事..

有趣的是，我的单元测试都通过了；包括，例如，调用ClientUser.objects.create()

这是 ClientUser 模型，虽然我不认为模型是问题（所有模型都会发生错误并且单元测试通过..）

class ClientUser(models.Model):
    guid = models.UUIDField(null=True, unique=True)
    username = models.CharField(max_length=256, null=True, unique=True)
    first_name = models.CharField(max_length=256, null=True)
    last_name = models.CharField(max_length=256, null=True)
    email = models.CharField(max_length=256, null=True)

    def most_recent_device(self):
        return self.devices.order_by('-pk').first()

    # I just put this classmethod in. I'm not sure if this will work, and went to the shell to try it, and that's when I noticed this issue. I've tried commenting it out and it makes no difference.    
    @classmethod
    def get_by_guid(cls, guid):
        return cls.objects.get(guid=guid)

这是来自 shell 的完整堆栈跟踪（上图）：

>>> from Interface.models import ClientUser
>>> ClientUser.objects.all()
Traceback (most recent call last):
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\sqlite3\base.py", line 303, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: Interface_clientuser

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "C:\Program Files\Python37\lib\site-packages\django\db\models\query.py", line 248, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "C:\Program Files\Python37\lib\site-packages\django\db\models\query.py", line 272, in __iter__
    self._fetch_all()
  File "C:\Program Files\Python37\lib\site-packages\django\db\models\query.py", line 1179, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\Program Files\Python37\lib\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 "C:\Program Files\Python37\lib\site-packages\django\db\models\sql\compiler.py", line 1068, in execute_sql
    cursor.execute(sql, params)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 100, in execute
    return super().execute(sql, params)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Program Files\Python37\lib\site-packages\django\db\utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Program Files\Python37\lib\site-packages\django\db\backends\sqlite3\base.py", line 303, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: Interface_clientuser

Answer 1

您的表尚未创建...

运行 makemigrations 以检查是否存在要应用的迁移

python manage.py makemigrations

然后运行 ​​migrate 将所有迁移应用到数据库中

python manage.py migrate

编辑您使用了多少个数据库？这个错误也是 sqlite 引发的，您是否在设置和测试中使用了 sqlite？

Answer 2

除此之外还需要额外的魔法：

python manage.py makemigrations
python manage.py migrate

运行这个奥术野兽：

python manage.py migrate --run-syncdb

欢欣鼓舞！：

C:\Code\Py\django\HealthCheck>python manage.py migrate --run-syncdb
Operations to perform:
  Synchronize unmigrated apps: Interface, messages, rest_framework, staticfiles
  Apply all migrations: admin, auth, contenttypes, sessions
Synchronizing apps without migrations:
  Creating tables...
    Creating table Interface_clientuser
    Creating table Interface_clientgroup
    Creating table Interface_device
    Creating table Interface_supportrequest
    Creating table Interface_fcmmessage
    Creating table Interface_healthcheckalert
    Running deferred SQL...
Running migrations:
  No migrations to apply.

C:\Code\Py\django\HealthCheck>python manage.py shell
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from Interface.models import ClientUser
>>> ClientUser.objects.all()
<QuerySet []>