how to fetch data from many to many field objects? - django

Question

I am getting stuck in many to many field objects in my model i want to retrieve the price of product from the order model objects but while fetching it gives sometime many related manager error or query set error
models.py
from django.db import models
from django.contrib import admin
from django.contrib.auth.models import User
class Product(models.Model):
name = models.CharField(max_length=100, db_index=True)
slug = models.SlugField(max_length=100, db_index=True)
description = models.TextField(blank=True)
price = models.DecimalField(max_digits=10, decimal_places=2)
available = models.BooleanField(default=True)
stock = models.PositiveIntegerField()
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
class Order(models.Model):
user = models.ForeignKey(User,on_delete= models.SET_NULL,null = True)
product = models.ManyToManyField('Order.Product')
is_ordered = models.BooleanField(default =False)
date_ordered = models.DateTimeField(auto_now = True,null = True)
views.py
def get_product_price(request):
if request.method=="GET":
user=User.objects.get(username = "hemant")
orders = user.order_set.all()
order = orders[0]
price = order.product.price
return HttpResponse(price)

Answer 1

When you are getting value from ManyToManyField, you need to do it like this:
products = order.product.all()
If you want to get the prices, you can do it like this:
products = order.product.all()
for product in products:
print(product.price)
If you want to return prices as a http response, then you can use values_list() to get list of prices from queryset. Like this
import json
views.py
def get_product_price(request):
if request.method=="GET":
user=User.objects.get(username = "hemant")
orders = user.order_set.all()
order = orders[0]
price = list(order.product.all().values_list('price', flat=True))
return HttpResponse(json.dumps(price))