Django多对多关系

问题描述

我有一个用户模型和一个组模型。

I have a user model and a group model.

 from django.contrib.auth.models import AbstractUser

 class Group(models.Model):
    name = models.CharField(max_length=200)

 class User(AbstractUser):
    name = models.CharField(max_length=200)
    group = models.ManyToManyField('Group')

我有用户可以是管理员或仅是组成员的方案。网上论坛可以有很多管理员，也可以有很多成员。
如何在Django中定义这样的关系并查询诸如组管理员，组成员，用户为管理员的组，用户为管理员的组之类的内容成员

I have a scenario in which a user can be an admin or just a member of a group. A group can have many admins as well as it can have many members.How can I define such a relation in Django and query things like "Admins of a group", "members of group", "groups where a user is an admin", "groups where a user is a member"

推荐答案

您应使用 ManyToMany 中介模型，并通过 '参数。

You should use ManyToMany intermediary model using 'through' argument.

class Group(models.Model):
    name = models.CharField(max_length=200)
    members = models.ManyToManyField(User, through='GroupMembership', related_name='groups')

class GroupMembership(models.Model):
    ROLE_CHOICE = (
        ('1', 'Admin'),
        ('2', 'Member'),
    )
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    group = models.ForeignKey(Group, on_delete=models.CASCADE)
    role = models.CharField(choices=ROLE_CHOICE, default='2', max_length=1)

组中的所有成员

group.members.all()

组的所有管理员

group.members.filter(groupmembership__role=1)

所有以'john'为管理员的组

All groups where 'john' is admin

Group.objects.filter(members__name='john', groupmembership__role=1)

用户为admin的组

user.groups.filter(groupmembership__role=1)

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