如何解决django中的循环导入错误？

Question

我知道该错误可能是由于循环导入错误，但对此知之甚少，我无法纠正它。我曾尝试使用类似问题中给出的方法，但无法解决。该项目有两个应用程序咨询和主要应用程序，我需要将它们的模型相互导入，

咨询/models.py

from django.db import models
from django.contrib.auth.models import User
from main.models import Customer


class Question(models.Model):
    name = models.ForeignKey(Customer, on_delete=models.CASCADE)
    type = models.CharField(max_length=100, default="SkinCare")
    title = models.CharField(max_length=1000)
    body = models.CharField(max_length=1000000)
    image = models.FileField(blank=True, default=None)
    time = models.DateTimeField()
    deltatime = models.IntegerField(default=0)

    def __str__(self):
        return str(self.time)


class Reply(models.Model):
    name = models.ForeignKey(Question, on_delete=models.CASCADE)
    user = models.ForeignKey(Customer, on_delete=models.CASCADE)
    text = models.CharField(max_length=10000000000)
    like = models.IntegerField(default=0)
    dislike = models.IntegerField(default=0)
    time = models.DateTimeField()
    deltatime = models.IntegerField(default=0)

    def __str__(self):
        return str(self.time)

main/models.py

from django.contrib.auth.models import User
from django.db import models
from consult.models import Question, Reply


class Customer(models.Model):
    name = models.ForeignKey(User, null=True)
    gender = models.CharField(max_length=100)
    skin_type = models.CharField(max_length=1000)
    hair_type = models.CharField(max_length=1000)
    bookmarked = models.ManyToManyField(Question)

    def __str__(self):
        return str(self.name)

当我运行尝试迁移应用程序时，出现以下错误：

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\site-packages\django-1.10.4-
py3.5.egg\django\core\management\__init__.py", line 367, in execute_from_
command_line
    utility.execute()
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\site-packages\django-1.10.4-
py3.5.egg\django\core\management\__init__.py", line 341, in execute
django.setup()
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\site-packages\django-1.10.4-py3.5.egg\django\__init__.py", line 27, 
in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\site-packages\django-1.10.4-py3.5.egg\django\apps\registry.py", line 
108, in populate
    app_config.import_models(all_models)
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\site-packages\django-1.10.4-py3.5.egg\django\apps\config.py", line 
199, in import_models
    self.models_module = import_module(models_module_name)
  File "C:\Users\Nikhil Khandelwal\AppData\Local\Programs\Python\Python35-
32\lib\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 "C:\New folder\WebD\zerovey\consult\models.py", line 3, in <module>
    from main.models import Customer
  File "C:\New folder\WebD\zerovey\main\models.py", line 3, in <module>
    from consult.models import Question, Reply
ImportError: cannot import name 'Question'

考虑到我是Django的初学者，请回答，在此先感谢您:)

Answer 1

在外键和多对多字段中使用to='<app_lable>.<Model Name>'

从文件中删除导入模型，在模型中添加外键和多字段，就像我在下面的代码中所做的那样。to='consult.Question' 当我们从 makemifration 命令创建迁移时，在迁移文件中使用硬编码模型名称，因此使用相同的方式编写 Foreignkey 和 Manytomany 字段

from django.contrib.auth.models import User 
from django.db import models
class Customer(models.Model): 
    name = models.ForeignKey(User, null=True) 
    gender = models.CharField(max_length=100)
    skin_type = models.CharField(max_length=1000)
    hair_type = models.CharField(max_length=1000)
    bookmarked = models.ManyToManyField(to='consult.Question')

    def __str__(self):
        return str(self.name)

Answer 2

尝试将您的导入更改为： 在咨询/models.py

import main.models.Customer

在 main/models.py 中

import consult.models.Question
import consult.models.Reply

然后你使用main.models.Customer而不是Customer，而不是Question或Reply你使用import consult.models.Question和consult.models.Reply

Answer 3

解决循环导入的另一种方法是：

from django.apps import apps
MyModel = apps.get_model('myapp', 'MyModel')