如何在Django REST Framework中合并两个反向外键为单个JSON字段

你可以通过DRF的SerializerMethodField自定义字段，合并两个反向关联的子对象ID，生成单独的children字段，完全在序列化器层面实现需求，无需修改模型。

修改后的序列化器代码 #

from rest_framework.serializers import ModelSerializer, SerializerMethodField
from .models import Person

class FamilySerializer(ModelSerializer):
    children = SerializerMethodField()

    def get_children(self, obj):
        # 收集当前对象作为母亲的孩子ID
        mother_children = [child.id for child in obj.children_as_mother.all()]
        # 收集当前对象作为父亲的孩子ID
        father_children = [child.id for child in obj.children_as_father.all()]
        # 合并列表并去重（防止同一孩子同时关联两个身份），再排序保证结果一致性
        combined_children = list(set(mother_children + father_children))
        combined_children.sort()
        return combined_children

    class Meta:
        model = Person
        fields = [
            "pk",
            "first_name",
            "last_name",
            "mother",
            "father",
            "children",
        ]

优化视图查询性能 #

为了避免序列化时出现N+1数据库查询问题，在视图集中给查询集添加预取关联：

from rest_framework.permissions import IsAuthenticated
from rest_framework.viewsets import ModelViewSet
from .models import Person
from .serializers import FamilySerializer

class FamilyViewSet(ModelViewSet):
    """
    API endpoint with family data
    """
    queryset = Person.objects.all().prefetch_related('children_as_mother', 'children_as_father')
    serializer_class = FamilySerializer
    permission_classes = [IsAuthenticated]

效果说明 #

修改后，API响应会生成你期望的JSON结构：每个Person对象都包含一个children字段，里面是该对象所有子女的ID集合，替换了原来的children_as_mother和children_as_father两个字段。

内容的提问来源于stack exchange，提问作者ap0