Submitting SUMMARY Data from Django to React using DRF-CodePudding

I'm starting to test some API data between django and React using Rest API. I'm able to submit this data between Djnago model and React front end.

[
    {
        "id": 1,
        "gender": "Male",
        "age": 40,
        "updated": "2022-04-25T18:55:23.304456Z",
        "created": "2022-04-25T14:07:48.282139Z"
    },
    {
        "id": 2,
        "gender": "Male",
        "age": 33,
        "updated": "2022-04-25T18:55:23.304456Z",
        "created": "2022-04-25T14:07:48.282139Z"
    },
    {
        "id": 3,
        "gender": "Female",
        "age": 22,
        "updated": "2022-04-25T18:55:23.304456Z",
        "created": "2022-04-25T14:07:48.282139Z"
    },
    {
        "id": 4,
        "gender": "Female",
        "age": 33,
        "updated": "2022-04-25T18:55:23.304456Z",
        "created": "2022-04-25T14:07:48.282139Z"
    },
]

My goal is not to submit this raw data, but instead to submit summary data (data analysis) that calculates the average age for males and females, so I should be getting something like this:

[
        {
            "gender": "Male",
            "average_age": 36.5,
        },
        {
            "gender": "Male",
            "average_age": 27.5,
        }
]

in TestDrf.js

import React from "react"
import axios from 'axios'


export default function App() {

    const [incomingData, setIncomingData] = React.useState([])

    React.useEffect(function() {
        console.log('effect ran')
        axios.get('http://127.0.0.1:8000/test/')
            .then(data => setIncomingData(data))
    }, [])
    
    return (
        <div>
            <pre>{JSON.stringify(incomingData.data, null, 2)}</pre>
        </div>
    )
}

in views.py

from rest_framework.response import Response
from rest_framework.decorators import api_view
from .models import Test
from .serializers import TestSerializer

@api_view(['GET'])
def getData(request):
    test_data= Test.objects.all()
    result = Test.objects.values('gender')
                           .annotate(average_age=Avg('age'))
    serializer = TestSerializer(test_data, many=True)
    return Response(serializer.data)

Where should I be making these cross tabulations? on the backend or front end? if on the backend should I be creating new models for the summary data?

I tried looking online for advice on this but I was unlucky!

CodePudding user response：

A Django query can be used in the backend to perform aggregation; new model is not needed for summary data.

An SQL query for getting average age by gender from a 'person' table would be something like this.

SELECT gender, AVG(age) AS average_age
FROM person
GROUP BY gender;

The equivalent Django query would be similar to this.

from django.db.models import Avg

result = Person.objects.values('gender')
                       .annotate(average_age=Avg('age'))

UPDATE: Adding a class based API view

class GetData(APIView):
        
    def get(self):
        
        result = Test.objects.values('gender').annotate(average_age=Avg('age'))
        
        response_data = {}
        response_data['data'] = list(result)
        
        return Response(response_data, status=status.HTTP_200_OK)

urls.py should be updated to use this API view.

path('getdata/', GetData.as_view()),