发出POST请求DRF时，此字段是必需的

Question

当我试图通过浏览器发布时，请求无法保存字段organization。你知道吗

发帖照片：

请提供以下我的代码。你知道吗

serializers.py：

class DescriptionOrganizationSerializer(serializers.PrimaryKeyRelatedField, serializers.ModelSerializer):

    class Meta:
        model = Organization
        fields = ("id", "org_name")


class DepartmentSerializer(serializers.ModelSerializer):
    emp_count_for_dep = serializers.SerializerMethodField()
    organization = DescriptionOrganizationSerializer(queryset=Organization.objects.all())

    class Meta:
        model = Department
        fields = '__all__'

models.py：

class Organization(models.Model):
    org_name = models.CharField(max_length=100)

    def __str__(self):
        return self.org_name


class Department(models.Model):
    dep_name = models.CharField(max_length=100)
    organization = models.ForeignKey(Organization, on_delete=models.CASCADE,
                                     related_name='departments')

    def __str__(self):
        return self.dep_name

views.py：

class DepartmentView(viewsets.ModelViewSet):

    queryset = Department.objects.all()
    serializer_class = DepartmentSerializer

错误：

所以我认为这可能是因为我添加了queryset=Organization.objects.all()和PrimaryKeyRelatedField——如果没有这些，我就无法选择organization字段并出现另一个错误（我解决了这个问题，但在这里提供它是因为这可以帮助您更好地理解我的代码）：

AssertionError at /api/v1/department/

The `.create()` method does not support writable nested fields by default.
Write an explicit `.create()` method for serializer `api.serializers.DepartmentSerializer`, or set `read_only=True` on nested serializer fields.

另一个想法是组织模型中的ForeignKey需要更改为OneToManyField之类的内容，但我不确定。你知道吗

希望你能看到，我在这里错过了什么

Answer 1

重写DepartmentSerializer类的to_representation()方法，并通过仅继承类来创建DescriptionOrganizationSerializer类。你知道吗

class DescriptionOrganizationSerializer(serializers.ModelSerializer):
    class Meta:
        model = Organization
        fields = ("id", "org_name")


class DepartmentSerializer(serializers.ModelSerializer):
    emp_count_for_dep = serializers.SerializerMethodField()

    class Meta:
        model = Department
        fields = '__all__'

    def to_representation(self, instance):
        rep = super().to_representation(instance)
        rep['organization'] = DescriptionOrganizationSerializer(instance.organization).data
        return rep

参考：DRF: Simple foreign key assignment with nested serializers? SO post