Question

我想存储哪个用户邀请了另一个用户到一个群组......但是django告诉我这是一个暧昧而违反规则（这是有道理的）。

groups.group：中介模式 Group_to_Member有多个用户的外键，即模棱两可，不允许。

那我该如何正确地做到这一点？也许是一般关系？可能会工作但似乎有点复杂......这就是我接近它的方式（删除了不相关的位）

from django.contrib.auth.models import User

class UserGroup(models.Model):
    members = models.ManyToManyField(User, through='Group_to_Member')

class UserGroup_to_Member(models.Model):
    group = models.ForeignKey(UserGroup)
    member = models.ForeignKey(User)

    invited_by = models.ForeignKey(User, related_name="group_invited_users")

解决方案

好的，所以我做了一些你们提供的答案的结合（谢谢！）和我在互联网上发现的东西以及我自己公认的微薄的python-fu：

from django.contrib.auth.models import User

class UserGroup(models.Model):
    # notice there is no member object here
    ... other model data

    def add_member(self, **kwargs):
        g2m = UserGroup_to_Member(group = self,  **kwargs)
        g2m.save()

    def remove_member(self, member):
        g2m = UserGroup_to_Member.objects.get(group=self, member=member)
        g2m.delete()

    # This is not elegant at all, help please? I'm pretty sure it isn't
    # as bad on the database as it looks though.
    def get_members(self):
        g2ms = UserGroup_to_Member.objects.filter(group=self)
        member_ids = [g2m.member.id for g2m in g2ms]
        members = User.objects.none()
        for id in member_ids:
            members = members | User.objects.get(id=id)
        return members

class UserGroup_to_Member(models.Model):
    group = models.ForeignKey(UserGroup)
    member = models.ForeignKey(User)

    invited_by = models.ForeignKey(User, related_name="group_invited_users")

Answer 1

您必须自己管理：

class MyGroup(models.Model):
    name = models.CharField(max_length=100)

class Membership(models.Model):
    group = models.ForeignKey(MyGroup)
    member = models.ForeignKey(User)

    invited_by = models.ForeignKey(User, related_name='invited_set')

然后代替group.members.all() group.membership_set.all()。

另外，我不会使用'Group'作为您的模型名称，因为Django已经有了一个Group对象。

Answer 2

如果您使用的是Django 1.7，则可以。

来自文档：https://docs.djangoproject.com/en/1.7/topics/db/models/#extra-fields-on-many-to-many-relationships

在Django 1.6及更早版本中，包含多个的中间模型任何参与多对多模型的外键以前的关系是被禁止的。

Django多对多的关系，并通过

解决方案

2 个答案: