Django 2：无法导入模型并保存

Question

我无法从其他应用导入我的模型。我已经查找并尝试过但不起作用。

events/models.py

class Registration(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    team = models.CharField(max_length=50, blank=True)
    date_created = models.DateTimeField(auto_now_add=True)

    def save(self, *args, **kwargs):
        payment = Payment.objects.create(registration=self)
        super().save(*args, **kwargs)

当我运行 python manage.py makemigrations 我明白了。

错误

File "C:\Users\Rubber\ems\events\models.py", line 5, in <module>
   from payments.models import Payment   
File "C:\Users\Rubber\ems\payments\models.py", line 6, in <module>
   from events.models import Registration 
ImportError: cannot import name 'Registration'

payments/models.py

import uuid

from django.db import models
from django.utils import timezone

from events.models import Registration  # THIS WONT WORK


def _create_uuid():
    return uuid.uuid1()

def _get_uuid():
    return _create_uuid()

class Payment(models.Model):
    uuid = models.CharField(max_length=1, default=_get_uuid)
    paid = models.BooleanField(default=False)
    registration = models.ForeignKey(Registration, on_delete=models.CASCADE)

我做错了什么？

Answer 1

您有一个循环导入。在这种情况下，您可以通过删除 Registration 导入并改用字符串来避免它：

class Payment(models.Model):
    registration = models.ForeignKey('events.Registration', on_delete=models.CASCADE)

另一种选择是将 Payment.objects.create() 代码移动到 signal 中。请注意，您当前的 save() 方法会在每次保存注册时创建一个 Payment ，这可能不是您想要的。

Django 2：无法导入模型并保存

Django 2: Can't import models and save it

python

django-2.0