在django中如何获取涉及多对多关系的对象列表 [英] how to get list of objects involving many to many relation in django

问题描述

我有以下模型：

class Committee(models.Model):
    customer = models.ForeignKey(Customer, related_name="committees")
    name = models.CharField(max_length=255)
    members = models.ManyToManyField(member, through=CommitteeMember, related_name="committees")
    items = models.ManyToManyField(Item, related_name="committees", blank=True)

class CommitteeRole(models.Model):
    committee = models.ForeignKey('Committee')
    member = models.ForeignKey(member)
    #user is the members user/user number
    user = models.ForeignKey(User)
    role = models.IntegerField(choices=ROLES, default=0)

class Member(models.Model):
    customer = models.ForeignKey(Customer, related_name='members')
    name = models.CharField(max_length=255)

class Item(models.Model):
    customer = models.ForeignKey(Customer, related_name="items")
    name = models.CharField(max_length=255)

class Customer(models.Model):
    user = models.OneToOneField(User, related_name="customer")
    name = models.CharField(max_length=255)

我需要获取属于所有用户的所有商品的所有项目通过 CommitteeRole 连接。

I need to get all of the Items that belong to all of the commitees in which a user is connected through the CommitteeRole.

如下所示：

committee_relations = CommitteeRole.objects.filter(user=request.user)
item_list = Item.objects.filter(committees=committee_relations__committee)

<

How can I accomplish this?

推荐答案

其实你已经完成了（几乎）：

Actually, you have already accomplished it (Almost):

committee_relations = CommitteeRole.objects.filter(user=request.user).values_list('committee__pk', flat=True)
item_list = Item.objects.filter(committees__in=committee_relations)

而且，如果您要查找单个查询，可以尝试这个：

And, if you are looking for a single query, you can try this:

items = Item.objects.filter(customer__committees__committeerole__user=request.user)

文档 here 和 here

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