When users purchase more than 1 product in in-app purchases, I want to increase the database to +1, so a user will be able to purchase a product 5 times. and will increase ( +1 ) for each product.
and when you gift this product to someone ( -1 ), it will decrease from the amount of the product you bought.
Do I need to use these functions?
What settings do I need to make to increase and decrease?

Can you help me ?
Thank You Soo Much
Kind Regards
I’m counting on you to help me with this. 