Question

我的简单models.py看起来像这样：

from django.db import models 

class Prescription(models.Model):
    pr_id = models.CharField()
    date_prescribed = models.DateTimeField()
    doctor = models.ForeignKey()
    pharmacy = models.ForeignKey()

我需要的是按月分组的处方总数。我针对上述要求提出的查询集如下：

prescriptions = Prescription.objects.extra(select={'month': connection.ops.date_trunc_sql('month', 'date_prescribed')}).filter(date_prescribed__range=(start_date,end_date)).values('month').annotate(Count('pr_id')).order_by('month')

其中end_date是今天的日期，start_date是六个月后的日期。此查询集按预期工作，我已在django shell上确认了这一点。

我需要JSON格式的数据，因为它最终需要发送到Angular中的折线图。我正在使用Django Rest框架进行序列化。我的views.py看起来像这样：

from django.db import connection
from datetime import date
from dateutil.relativedelta import relativedelta
from django.db.models import Count
from rest_framework.decorators import api_view
from rest_framework.response import Response
from testproj.models.Prescription import Prescription 
from testproj.serializers.AnalyticsSerializer import LineGraphSerializer


@api_view(['GET'])
def prescription_trend_overview(request):

    end_date = date.today()
    start_date = date.today() + relativedelta(months=-6)
    prescriptions = Prescription.objects.extra(select={'month': connection.ops.date_trunc_sql('month', 'date_prescribed')}).filter(date_prescribed__range=(start_date,end_date)).values('month').annotate(Count('pr_id')).order_by('month')
    serializer = LineGraphSerializer(prescriptions, many=True)
    return Response(serializer.data)

我的serializer.py看起来像这样：

from rest_framework import serializers

class LineGraphSerializer(serializers.Serializer):
    total_prescriptions = serializers.IntegerField()    
    timeline = serializers.DateField()

然而，我最终进入浏览器DRF页面的数据显示所有内容为空。

我怀疑问题在于序列化，因为查询集正常工作。任何帮助

Answer 1

抱歉，我无法发表评论，所以..

我对QuerySet了解不多，但是，试试这个：

class LineGraphSerializer(serializers.Serializer):
    total_prescriptions = serializers.SerializerMethodField()   
    timeline = serializers.SerializerMethodField()

    def get_total_prescriptions(self,*args, **kwargs):
        #print kwargs and look data
        #return <requiere data>

    def get_timeline(self,*args, **kwargs):
        #print kwargs and look data
        #return <requiere data>

PD 1：你能在shell上给我们打印QuerySet吗？

PD 2：我还不能发表评论，再次抱歉

Django数据序列化的问题

1 个答案: