I am trying to make a db which has Product . A product can be stored in 1 or more different place (stockRoom). When i want to make a sale of a product then:
First i want to know what is the current stock of product in each stocKRoom , Second i want to sale a Qty of product , from one of stockRooms.
The Qty of product must be decrease the stock of StokRoom. (If i sale 2 product from "stockRoom1" the stock of this stockRoom must be decrease by 2)