如何从ForeignKey';Django queryset中的s相关模型?
使用外键访问相关模型中的字段时遇到问题 我有两种模式,个人和政党,如下所述:如何从ForeignKey';Django queryset中的s相关模型?,django,Django,使用外键访问相关模型中的字段时遇到问题 我有两种模式,个人和政党,如下所述: class Person(models.Model): title = models.CharField(max_length = 4, blank=True, null=True) first = models.CharField(max_length = 30, blank=True, null=True) last = models.CharField(max_length = 30, b
class Person(models.Model):
title = models.CharField(max_length = 4, blank=True, null=True)
first = models.CharField(max_length = 30, blank=True, null=True)
last = models.CharField(max_length = 30, blank=True, null=True)
party = models.ForeignKey(Party, related_name = 'parties', on_delete=models.CASCADE, blank=True, null=True)
def __str__(self):
return self.id
class Party(models.Model):
party_name = models.CharField(max_length = 50)
party_code = models.CharField(max_length = 5)
def __str__(self):
return self.party_name
我想让每一方都有多少人。我希望结果如下所示:
[{
"party_name": "Democrat",
"total_members": 93
},
{
"party_name": "Republican",
"total_members": 32
},
{
"party_name": "Non-Partisan",
"total_members": 34
}]
我的序列化程序如下所示:
class CountPartiesSerializer(serializers.ModelSerializer):
total_members = serializers.IntegerField()
class Meta:
model = Person
fields = ('id', 'party', 'total_members')
class CountPartiesViewSet(DefaultsMixin, viewsets.ModelViewSet):
queryset = Person.objects.values('party__party_name').annotate(total_members = Count('id'))
serializer_class = CountPartiesSerializer
我的视图集如下所示:
class CountPartiesSerializer(serializers.ModelSerializer):
total_members = serializers.IntegerField()
class Meta:
model = Person
fields = ('id', 'party', 'total_members')
class CountPartiesViewSet(DefaultsMixin, viewsets.ModelViewSet):
queryset = Person.objects.values('party__party_name').annotate(total_members = Count('id'))
serializer_class = CountPartiesSerializer
但这会导致以下结果:
[{
"party": null,
"total_members": 34
},
{
"party": null,
"total_members": 93
},
{
"party": null,
"total_members": 32
}]
我尝试过无数种不同的方法,我知道我遗漏了一些东西,但我不知道如何让它起作用。任何建议都将不胜感激 您序列化了错误的内容。序列化程序应基于参与方,然后可以添加成员数 编辑
class PartySerializer(serializers.ModelSerializer):
total_members = serializers.IntegerField()
class Meta:
model = Party
fields = ('name', 'total_members')
class PartyViewSet(DefaultsMixin, viewsets.ModelViewSet):
queryset = Party.objects.values('name').annotate(total_members=Count('parties'))
serializer_class = PartySerializer
你当然有一个党和人之间的关系:这是你的外键的反向关系。请注意,您选择的相关_名称令人困惑;它应该是“people”,或者将其保留为默认值,即“person\u set”。谢谢!你能详细说明一下我会怎么做吗?我不确定我的PartySerializer在这种情况下会是什么样子,也不确定我将如何获得对人数的引用(因为如果有任何意义的话,PartySerializer与Person模型是没有关系的)。非常感谢-这很有效!我还在想着在Django的关系。