CODEWITHSUNDEEP
django
Ajay Khajindar
Ajay Khajindar

Reputation: 33

How to access sum of reverse foreign key single field using template filter in django?

Suppose I have 2 models Customer & Account.

Models

class Account(models.Model):

    customer = models.ForeignKey(Customer,on_delete=models.CASCADE,
               blank=True,null=True,related_name='account')
    desc = models.CharField(max_length=100)
    paid = models.IntegerField(default=0)
    received = models.IntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

class Customer(models.Model):

    name = models.CharField(max_length=30,unique=True)
    contact = models.CharField(max_length=10)

I want to access Sum of received & Sum of paid field in template

Customer View

def show_customer(request,id=None):

    customer = Customer.objects.filter(user=request.user)

    return render(request,'customer/show_customer.html',{'customer':customer})

show_customer.html

<html>
{% for cust in customer %}
    {{cust.name}}
    {{cust.contact}}
    **Here I want sum of paid & sum of receive for current customer**
</html>

Upvotes: 1

Views: 416

Answers (1)

Jeet
Jeet

Reputation: 372

You can make use of django models @property decorator.

Your Customer model

class Customer(models.Model):

    name = models.CharField(max_length=30,unique=True)
    contact = models.CharField(max_length=10)

    @property
    def received_amount(self):
        return self.account.all().aggregate(Sum('received'))['received__sum']

    @property
    def paid_amount(self):
        return self.account.all().aggregate(Sum('paid'))['paid__sum']

And then you can access it in your template

<html>
{% for cust in customer %}
    {{cust.name}}
    {{cust.contact}}
    {{ cust.received_amount }}
    {{ cust.paid_amount }}
</html>

Hope this will help you out!

Upvotes: 3

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