Question

在此项目中，我们为教室中的学生分配了徽章。

class Badge(models.Model):
    klass = models.ForeignKey( # klass means classroom
        'klass.Class',
        on_delete=models.CASCADE,
        related_name='badges',
        db_index=True,
    )
    users = models.ManyToManyField( # the students in 'klass' that have this badge
        User,
        through='UserBadge',
        through_fields=('badge', 'user'),
    )

users ManyToMany字段的自定义中间表：

class UserBadge(models.Model):
    user = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name='taken_badges',
    )
    badge = models.ForeignKey(
        Badge,
        on_delete=models.CASCADE,
        related_name='assigned_badges',
    )
        klass = models.ForeignKey( # this classroom is badge.klass
        'klass.Class',
        on_delete=models.CASCADE,
        related_name='assigned_badges',
    )

我需要找到与特定user和klass相关的所有徽章。这样我就可以检索特定教室中特定学生的所有徽章。

我尝试过：

Bagde.objects.filter(userbadge__user__id = student_id,userbadge__klass__id=klass_id)

，错误是： Cannot resolve keyword 'userbadge' into field. 谢谢。

Answer 1

由于您将related_name设置为'assigned_badges'，因此应将过滤器实现为：

Bagde.objects.filter(
    assigned_badges__user__id=student_id,
    assigned_badges__klass__id=klass_id
)

在多关系中的查询集

1 个答案: