Django序列化程序未将数据保存到数据库，但响应正常

Question

下面的序列化程序不保存对数据库的更改，但来自API的JSON响应有新的正确值！ 怎么了？在

class FieldSerializer(serializers.ModelSerializer):
    class Meta:
        model = Field
        fields = 'id', 'name', 'default'

class DocumentSerializer(serializers.HyperlinkedModelSerializer):
    field = FieldSerializer(many=False, read_only=True)

    def _save_field(self, instance):
        field = self.initial_data.pop('field', None)
        field_ids = field['id']
        field = Field.objects.get(pk=field_ids)
        instance.field = field

    def save(self, **kwargs):
        instance = super().save(**kwargs)
        self._save_field(instance)

Answer 1

设置字段后，您不会保存instance：

def _save_field(self, instance):
    field = self.initial_data.pop('field', None)
    field_ids = field['id']
    field = Field.objects.get(pk=field_ids)
    instance.field = field
    instance.save()  # <  mandatory

该字段被正确地归因于已序列化的实例，但没有保存到数据库中，这就是为什么您看到新值的正确响应。在