Блог

Я хотел бы вычислить ‘total’ для каждой строки, используя следующий код, он показывает только итоговую сумму в последней строке, а не в каждой строке.

 class Invoice(models.Model):
    date = models.DateField(default=timezone.now)
    client = models.ForeignKey(Client,on_delete=models.CASCADE)

    def total(self):
        items = self.invoiceitem_set.all()
        for item in items:
            amount_due = (item.price * item.quantity)
        return round(amount_due, 2)

class InvoiceItem(models.Model):
    invoice = models.ForeignKey('Invoice', on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    price = models.DecimalField(max_digits=20, decimal_places=2)
    quantity = models.DecimalField(max_digits=20, decimal_places=2)
  

 {% for product in object.invoiceitem_set.all %}
<tr>
    <td>{{product.product}}</td>
    <td>{{product.price}}</td>
    <td>{{product.quantity}}</td>
    <td>{{object.total}}</td>
</tr>
{% endfor %}
  

Вы можете попробовать что-то вроде этого:

 class Invoice(models.Model):
    date = models.DateField(default=timezone.now)
    client = models.ForeignKey(Client,on_delete=models.CASCADE)
    # Total field for each invoice
    total = models.DecimalField(max_digits=20, decimal_places=2, default=0)


class InvoiceItem(models.Model):
    invoice = models.ForeignKey('Invoice', on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    price = models.DecimalField(max_digits=20, decimal_places=2)
    quantity = models.DecimalField(max_digits=20, decimal_places=2)
    
    # Overriding the save method to update invoice total for each new item
    def save(self, *args, **kwargs):
        self.invoice.total  = round(self.price * self.quantity, 2)
        self.invoice.save()
        super().save(*args, **kwargs)
  

 {% for product in object.invoiceitem_set.all %}
<tr>
    <td>{{product.product}}</td>
    <td>{{product.price}}</td>
    <td>{{product.quantity}}</td>
    <td>{{product.invoice.total}}</td>
</tr>
{% endfor %}