Django：模型内部的定义方法

Question

django Tools_booked类中包含的serialize（）方法，但尝试访问该方法时显示错误。

'QuerySet' object has no attribute 'serialize'

models.py

from django.core.serializers import serialize
class UpdateQuerySet(models.QuerySet):
    def serialize(self):
        print("*****Entered the serizlize inside the  UpdateQuerySet models **********")
        qs = self
        return serialize('json', qs, fields=('auto_increment_id','user','component','booked'))

class UpdateManager(models.Manager):
    def get_queryset(self):
        return UpdateQuerySet(self.model, using=self._db)

class Tools_booked(models.Model):
    auto_increment_id = models.AutoField(primary_key=True)
    user=models.ForeignKey(Profile, on_delete=models.CASCADE)
    component = models.CharField(max_length=30, blank=True)
    booked = models.DateTimeField(auto_now_add=True,blank=True)

    objects = UpdateManager()

    def __str__(self):
        return self.component

    def serialize(self):
        json_data = serialize("json", [self], fields=['auto_increment_id','user','component','booked'])
        stuct = json.loads(json_data)
        print(struct)
        data = json.dump(stuct[0]['fields'])
        return data

views.py

class SerializedDetialView(View):
     def get(self, request, *args, **kwargs):
        print("*****Entered the SerializedDetialView **********")
        obj_list= Tools_booked.objects.filter(auto_increment_id=1)
        json_data = obj_list.serialize()
        return HttpResponse(json_data, content_type='application/json')


class SerializedListView(View):
     def get(self, request, *args, **kwargs):
        json_data = Tools_booked.objects.all().serialize()
        return HttpResponse(json_data, content_type='application/json')

错误回溯

 json_data = Tools_booked.objects.all().serialize()
AttributeError: 'QuerySet' object has no attribute 'serialize'

但是这可行。

class SerializedDetialView(View):
     def get(self, request, *args, **kwargs):
        obj_list= Tools_booked.objects.filter(auto_increment_id=1)
        json_data = serializers.serialize("json", obj_list )
        return HttpResponse(json_data, content_type='application/json')


class SerializedListView(View):
     def get(self, request, *args, **kwargs):
        qs = Tools_booked.objects.all()
        json_data = serializers.serialize("json", qs )
        return HttpResponse(json_data, content_type='application/json')

如何在models.py，Tools_booked类中使用serialize（）方法。

Answer 1

您应该将Django-rest框架序列化程序与many=True一起使用，或者使用Django queryset的values()函数。无需在模型中编写函数。它将像这样工作

class YourSerializer(serializers.ModelSerializer):
     class Meta:
        model = "You Model Here"
        fields = "write list of your model fields here or user __all__ for all fields"

您可以像这样序列化查询

queryset = Your_Model.objects.all()
serialized = YourSerializer(queryset, many=True).data

其他方法是这样的

serialized = Your_Model.objects.all().values()

此方法看起来很简单，但是如果您要编写Rest API，则应使用序列化程序。您可以查看串行器here的详细信息。