Django的：扩展用户模型轮廓onetoonefield错误

Question

我有这个模型

from django.contrib.auth.models import User 
from django.db import models 
from django.db.models.signals import post_save 
from django.dispatch import receiver 

from my_app.models import Teams 

class Profile(models.Model): 
    user = models.OneToOneField(User, on_delete=models.CASCADE) 
    team = models.ForeignKey(Teams, on_delete=models.CASCADE) 

    class Meta: 
     app_label = 'my_app' 

    def __str__(self): 
     return self.name 

@receiver(post_save, sender=User) 
def create_user_profile(sender, instance, created, **kwargs): 
    if created: 
     Profile.objects.create(user=instance) 

@receiver(post_save, sender=User) 
def save_user_profile(sender, instance, **kwargs): 
    instance.profile.save() 

我然后进入壳

from django.contrib.auth.models import User 

当我输入

user = User.objects.create_user(username='test', email='dummyemail@dum.com', password='test') 

我意料之中得到

IntegrityError: NOT NULL constraint failed: my_app_profile.team_id 

但是当我键入

user = User.objects.create_user(username='test', email='dummyemail@dum.com', password='test', team='developer') 

我得到

TypeError: 'team' is an invalid keyword argument for this function 

如果键入

user = User.objects.create_user(username='test', email='dummyemail@dum.com', password='test', profile.team='developer') 

我得到

SyntaxError: keyword can't be an expression 

任何帮助，提示或指导，将不胜感激

Answer 1

您尚未允许团队为空，所以当你创建像这样的轮廓：

@receiver(post_save, sender=User) 
def create_user_profile(sender, instance, created, **kwargs): 
    if created: 
     # Team isn't defined 
     Profile.objects.create(user=instance) 

你会得到一个错误。

允许团队为空（或在代码中设置默认以上）：

class Profile(models.Model): 
    user = models.OneToOneField(User, on_delete=models.CASCADE) 
    team = models.ForeignKey(Teams, on_delete=models.CASCADE, null=True) 

    class Meta: 
     app_label = 'my_app' 

    def __str__(self): 
     return self.name 

Answer 2

当您运行

User.objects.create_user(username='test', email='dummyemail@dum.com', password='test') 

你因为post_save信号IntegrityError。它试图创建一个Profile实例，但在Profile模型team不能是NULL。 By default, model fields have null=False。

当您运行

user = User.objects.create_user(username='test', email='dummyemail@dum.com', 
    password='test', team='developer') 

你得到错误，因为team是Profile模式，而不是User模型的字段。

当您运行

user = User.objects.create_user(username='test', email='dummyemail@dum.com', 
    password='test', profile.team='developer') 

，因为你不能使用.参考属性你会得到错误。您需要使用__来过滤外键属性。例如，请参阅this问题。但是，即使您使用__，它仍然会出现错误，因为它们在User模型中没有名为profile的字段。

我会建议的另一件事是将post_save信号合并为一个，因为两者都具有相同的发件人。

Answer 3

参见the documentation约ForeignKey.related_name。默认情况下，OneToOneField具有相关名称以将一个模型连接到另一个模型，但ForeignKey不会。只要有这个选项，你可以做user.team来访问相关的模型。

class Profile(models.Model): 
    user = models.OneToOneField(User, on_delete=models.CASCADE) 
    team = models.ForeignKey(Teams, 
          on_delete=models.CASCADE, 
          related_name='team', 
          null=True)