小编Zev*_*Zev的帖子

在我的Django项目中,当我查询数据时,我得到以下错误:

django.db.utils.OperationalError:(1052,"字段列表中的列'名称'含糊不清")

使用:

http://localhost:8000/api/physicalserver/list/?switchesport__bandwidth=10

但如果我使用:

http://localhost:8000/api/physicalserver/list/?switches__id=xxx

它会工作正常.

我的ListAPIView代码:

class PhysicalServerListAPIView(ListAPIView):
    serializer_class = PhysicalServerListSerializer
    permission_classes = [AllowAny]
    pagination_class = CommonPagination
    def get_queryset(self):
        query_params = self.request.query_params
        filters = {'{}__contains'.format(key): value
               for key, value in query_params.items()
               }
        qs = PhysicalServer.objects.filter(**filters)
        return qs.extra(select={'length':'Length(name)'}).order_by('length', 'name')

我的序列化代码:

class PhysicalServerListSerializer(ModelSerializer):
    bandwidth = serializers.SerializerMethodField()

    class Meta:
        model = PhysicalServer
        fields = "__all__"
        depth = 1

    def get_bandwidth(self, obj):
        return obj.switchesport.bandwidth

我的物理服务器模型:

class PhysicalServer(models.Model):         
    name = models.CharField(max_length=32)

    switches = models.ForeignKey(to=Switches, on_delete=models.DO_NOTHING)
    physical_server_model = models.ForeignKey(to=PhysicalServerModel, null=True, on_delete=models.DO_NOTHING)
    switchesport = models.OneToOneField(to=SwitchesPort, …

我遇到了一个与PostgreSQL查询类似的问题，但限制为1的速度非常慢，而带ORDER和LIMIT子句的PostgreSQL 速度非常慢，尽管在我的情况下，是否LIMIT为1、5或500 都没有关系。

基本上，当我无限制地运行由Django的ORM生成的查询时，该查询花费了半秒钟，但有限制（为分页而增加）则需要7秒钟。

耗时7秒的查询是：

SELECT "buildout_itemdescription"."product_code_id",
         MIN("buildout_lineitem"."unit_price") AS "min_price"
FROM "buildout_lineitem"
INNER JOIN "buildout_itemdescription"
    ON ("buildout_lineitem"."item_description_id" = "buildout_itemdescription"."id")
WHERE (("buildout_lineitem"."report_file_id" IN (154, 172, 155, 181, 174, 156, 157, 182, 175, 176, 183, 158, 177, 159, 179, 178, 164, 180, 367, 165, 173, 166, 167, 168, 368, 422, 370, 169, 1335, 1323, 161, 160, 162, 170, 171, 676, 151, 163, 980, 152, 369, 153, 963, 1718, 881, 617, 1759, 1780, …