如何使用Django创建三重连接表

from django.db import models

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

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

class AB(models.Model):
    a = models.ForeignKey(A, on_delete=models.CASCADE)
    b = models.ForeignKey(B, on_delete=models.CASCADE)

class A(models.Model):
    name = models.CharField(max_length=100)
    bs = models.ManyToManyField(B, through='AB')

class B(models.Model):
    name = models.CharField(max_length=100)
    as = models.ManyToManyField(A, through='AB')

a = A.objects.get(name='example A')
related_bs = a.bs.all()

b = B.objects.get(name='example B')
related_as = b.as.all()

# 添加关系
a = A.objects.get(name='example A')
b = B.objects.get(name='example B')
a.bs.add(b)

# 更新关系
ab = AB.objects.get(a=a, b=b)
ab.save()

# 删除关系
a.bs.remove(b)