order item collection with
quantity field, and
total price field.
When user press add button to add more of the order item,
quantity field is set to be updated as
current order item quantity+1
Total price field is set as
(current order item quantity+1)Xproduct price
Reverse is with minus when reducing the order item.
The problem is when pressed add button and minus button one after another frequently, the calculation confuses.
I think updating the fields at the same time fails.