Why is my save method not returning any value-CodePudding

When I do

investment.basic_interest

I get 0. Why is it returning 0? I feel my save method is not properly written. Any idea where the problem is coming from?


class Investment(models.Model):
    basic_deposit_amount = models.IntegerField(null=True)
    basic_interest = models.IntegerField(null=True)

    def save(self, *args, **kwargs):
        self.basic_interest =  self.basic_deposit_amount * 365 * 0.02/2  #calculated field. 
        super(Investment, self).save(*args, **kwargs)

Views

def create_investment_view(request):
    if request.method == 'POST':
        basic_investment_form = BasicInvestmentForm(request.POST)
    
        if basic_investment_form.is_valid():
            investment = basic_investment_form.save(commit=False)
            investment.basic_investment_return  = investment.basic_deposit_amount
            print(investment.basic_interest)
            print(investment.basic_investment_return)
            print(investment.basic_deposit_amount)
            investment.is_active = True
            investment.save()
            messages.success(request, 'your basic investment of {} is successfull '.format(investment.basic_deposit_amount))
        else:
            messages.success(request, 'your investment is not successfull! Try again.')
    else:
        basic_investment_form = BasicInvestmentForm()
        
    context = {'basic_investment_form': basic_investment_form}
    return render(request, 'create-basic-investment.html', context)

CodePudding user response：

It depends on where you are checking the value of investment.basic_interest in your code. The piece of code you have is executed only when the instance is saved (after the save() method is called).

def test_view(request):
    investment = Investment()
    investment.basic_deposit_amount = 100

    print(investment.basic_interest) # Prints 0

    investment.save()

    print(investment.basic_interest) # Prints 365.0

CodePudding user response：

You need to return what super() method does. Add return to last line:

def save(self, *args, **kwargs):
    self.basic_interest =  self.basic_deposit_amount * 365 * 0.02/2  #calculated field. 
    return super(Investment, self).save(*args, **kwargs)