django'int'對象沒有屬性'save'

Question

我是django的新手，我收到以下代碼的錯誤，我想它很簡單，但我真的不明白。

from django.db.models.signals import post_save
from django.dispatch import receiver

from myapp.models import MyModel1, MyModel2


@receiver(post_save, sender=MyModel1)
def test_signal(sender, **kwargs):
    #import pdb;pdb.set_trace();
    if kwargs['instance']:
        instance = kwargs['instance']

        if instance.old_processed_value == False and instance.processed == True:
            var1 = MyModel2.objects.get(val1= instance.val1, val2 = instance.val2)
            var2 = var1.quantity+instance.qty_change
            var2.save()

Answer 1

我認為應該是：

var1.quantity += instance.qty_change
var1.save()

Answer 2

var1 = MyModel2.objects.get(val1= instance.val1, val2 = instance.val2)

var1是MyModel2對象，名稱錯誤

var1具有save（）方法，但是var2是int值，因此會發生錯誤

您想做什么：

model2_obj = MyModel2.objects.get(val1= instance.val1, val2 = instance.val2)
model2_obj.quantity+instance.qty_change
model2_obj.save()