用于向后相关字段的Django查询集过滤器

Question

如何根据与之相关的模型过滤模型？下面的例子......这是有效的,但我认为这次击中了DB两次并且非常不优雅.有没有办法直接使用查询集？也许某种程度上select_related(),但一直没能想到那一个.我想返回QuerySet的Project.

from django.db import models

class Person(models.Model):
    pass

class Project(models.Model):
    pass

class Action(models.Model):
    person = models.ForeignKey(Person)
    project = models.ForeignKey(Project)

# Better way to do this?
def projects_by_person(person):
    actions = Action.objects.filter(person=person)
    project_ids = actions.values_list('project')
    return Project.objects.filter(id__in=project_ids)

Answer 1

试试这个.我没有测试过,如果您有任何问题请告诉我

#Untested Code
Project.objects.filter(action__person = person)