如何在Django中跨三个关联模型查询用户所属全部Campaign

我正在使用Django，希望了解如何通过三个关联模型获取对象。以下是我的模型代码：

class Participant(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    is_leader = models.BooleanField(default=False)
    team = models.ForeignKey(Team, on_delete=models.CASCADE, null=True, related_name="participants")
    application_date = models.DateField(auto_now_add=True, null=True)
    resolution_date = models.DateField(null=True, blank=True)
    accepted = models.BooleanField(default=False)

class Team(models.Model):
    name = models.TextField(default="")
    is_public = models.BooleanField(default=False)
    institution = models.ForeignKey(Institution, on_delete=models.CASCADE, null=True, related_name='teams')
    campaign = models.ForeignKey(Campaign, on_delete=models.CASCADE, null=True, related_name='teams')

class Campaign(models.Model):
    name = models.TextField(default="")
    description = models.TextField(default="")
    initial_date = models.DateTimeField(auto_now_add=False, null=True, blank=True)
    end_date = models.DateTimeField(auto_now_add=False, null=True, blank=True)
    qr_step_enabled = models.BooleanField(default=True)
    image_resolution = models.IntegerField(default=800)
    sponsor = models.ForeignKey(Sponsor, on_delete=models.CASCADE, null=True, related_name='campaigns')

我已通过request获取到user对象，想要获取该用户所属的全部Campaign。原本我使用循环实现：

user = request.user
participants = user.participant_set.all()
for participant in participants:
  participant.team.campaign.name

请问是否可以通过跨模型查询实现该需求？用户可拥有多个Participant，每个Participant对应一个Team，每个Team对应一个Campaign。

当然可以通过Django的跨模型关联查询直接实现，不需要循环遍历，还能避免N+1数据库查询问题，提升效率。以下是几种可行方式：

方式一：从Campaign模型反向关联查询 #

利用Django的双下划线__实现跨模型筛选，直接定位到关联当前用户的Campaign：

user = request.user
campaigns = Campaign.objects.filter(teams__participants__user=user).distinct()

• teams__participants__user表示：Campaign关联的Team → Team关联的Participant → Participant关联的User等于当前用户
• .distinct()用于去重，避免同一个Campaign因用户多个Participant关联而重复出现

方式二：从User模型正向关联查询 #

从当前用户出发，通过关联的Participant、Team反向定位到Campaign：

user = request.user
# 获取完整的Campaign对象
campaigns = Campaign.objects.filter(id__in=user.participant_set.values_list('team__campaign__id', flat=True)).distinct()

# 若只需获取Campaign的ID，可直接用values_list
campaign_ids = user.participant_set.values_list('team__campaign__id', flat=True).distinct()

方式三：优化原循环逻辑（可选） #

如果需要保留循环处理逻辑，可通过select_related预加载关联对象，减少数据库查询次数：

user = request.user
# 提前预加载team和campaign，仅发起1次数据库查询
participants = user.participant_set.select_related('team__campaign').all()
for participant in participants:
    print(participant.team.campaign.name)

内容的提问来源于stack exchange，提问作者RaimundoDiaz