Django: how do i substract numbers from another number and return the new_value in django

Question

I have a model field called main_all_earning and it looks like this main_all_earning = models.IntegerField(default=0), I also have a form where user are allowed to input any amount they want to withdraw from main_all_earning, I have written the logic for it to subtract the value from the form which is called amount from the main_all_earning, but the main_all_earning does not update. What could be the issue?

Views.py:


def withdrawal_request(request):
    user = request.user
    profile = Profile.objects.get(user=user)
    main_all_earning = profile.main_all_earning
    if request.method == "POST":
        form = WithWithdrawalRequestForm(request.POST)
        if form.is_valid():
            new_form = form.save(commit=False)
            new_form.user = request.user
            if ...:
                pass
            else:
                new_form.save()
                main_all_earning = main_all_earning - new_form.amount
                return redirect("core:withdrawal-request")
    else:
        ...
    context = { "form":form, "main_all_earning":main_all_earning,}
    return render(request, "core/withdrawal-request.html", context)

Asked By: Destiny Franks

||

Source

Answer 1

You set the main_all_earning variable here:

main_all_earning = main_all_earning - new_form.amount

But you don’t actually set it on the profile or save it:

profile.main_all_earning = main_all_earning - new_form.amount
profile.save()

Answered By: 0sVoid

Answer 2

You need to save it on the profile like this

## chain the main_all_earning to the profile object
profile.main_all_earning = main_all_earning - new_form.amount
## Save the new value
profile.save()

Answered By: Benjamin

Django: how do i substract numbers from another number and return the new_value in django

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