Django不对称自我通过关系查询 [英] Django asymettrical self through relationship query

问题描述

我有以下简化模型：

class User(models.Model):
    following = models.ManyToManyField("self", through='Following', symmetrical=False)

class Following(models.Model):
    from_user = models.ForeignKey(User, related_name='from_user')
    to_user = models.ForeignKey(User, related_name='to_user')
    status = models.IntegerField()

状态为0，待处理为1，以下为
让用户成为用户。我想获得用户的所有追踪用户

The status is 0 for pending, 1 for following Let user be a User. I would like to get all the followed users of user

我可以做

user.following.all()

获取用户所关注的所有用户（待处理关系或者真的跟着）

to get all the users user is following (pending relationships OR really follow)

或

Following.objects.filter(from_user=user, status=1)

获取用户用户和真实友谊的所有关注对象

to get all the Following objects with User user and real friendship

但是如何获取user和status = 1的所有User对象？
我似乎找不到一种方式

But how can I get all the User objects for user and status=1 ? I can't seem to find a way

谢谢！

推荐答案

尝试

user.following.filter(to_user__status=1)

user.following 仍在查询 code>，因此您需要将关系w / __ 到跟随在这里。

这两个字段 from_user 和 to_user 都是 ForeignKey 指向用户模型。因此，对于 User（）实例 u ：

The two fields here, from_user and to_user, are both ForeignKey pointing to User model. Thus for an User() instance u:

• u.following 搜索 User（） s谁有关系w / u 通过中间表，跟随。关键在于 u.following 在跟随 ForeignKey c $ c>指向用户，作为 u 本身的引用。因此，对于您的版本跟随， u.following.filter（to_user__status = 1）过滤器关注具有 from_user 的项目等于 u 和 to_user w / status 等于 1 。查找是典型的以下关系向后


• u.from_user 在中间表中搜索具有 from_user 等于 u


• u.to_user 在中间表中搜索具有 to_user 等于 u

• u.following searches for the User()s who have relationship w/ u through the intermediate table, the Follow. The key here is that u.following picks the first ForeignKey in the Follow that points to the User, as the reference to u itself. Thus for your version of Follow, u.following.filter(to_user__status=1) filters on the Follow items having from_user equals to u and to_user w/ status equals to 1. The lookup is typical following relationship backwards
• u.from_user searches the intermediate table for those having from_user equals to u
• u.to_user searches the intermediate table for those having to_user equals to u

另外，您可以直接过滤 ForeignKey ，记住 from_user 和 to_user 都是参考跟随：

Also, you could filter on the ForeignKey directly, w/ remembering that the from_user and to_user are both ref the Follow:

User.objects.filter(to_user__from_user=user, to_user__status=1) # user as from_user
User.objects.filter(from_user__to_user=user, from_user__status=1) # user as to_user
User.objects.filter(following=user) # those who are followed by `to_user` user

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