Question

我有以下型号：

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

# Create your models here.
class CommonUser(models.Model):
  user = models.OneToOneField(User)
  field = models.CharField(max_length=20)

class SpecificUserA(models.Model):
  user = models.OneToOneField(CommonUser)
  field_a = models.CharField(max_length=20)

class SpecificUserB(models.Model):
  user = models.OneToOneField(CommonUser)
  field_b = models.CharField(max_length=20)

这使我可以在SpecificUserA和SpecificUserB之间共享信息。这不会阻止我为一个SpecificUserA对象创建SpecificUserB和User对象：

u = User.objects.create_user(username='user1')
u.save()

u.commonuser = CommonUser(field="user1 field data")
u.commonuser.save()

u.commonuser.specificusera = SpecificUserA(field_a="user1 field_a data")
u.commonuser.specificusera.save()

# how can I prevent this?
u.commonuser.specificuserb = SpecificUserB(field_b="user1 field_b data")
u.commonuser.specificuserb.save()

我知道在创建User对象之前，我可以设置条件来检查具有特定用户名的Specific对象是否存在，但是是否有检查可以捕获上述场景？

防止创建模型对象

0 个答案: