barcode sales balance sales return
1000 1 9 1
1001 0 10 0
1002 0 10 0
1003 0 10 0
we have to throw error as balance stock in 1000 is 9 ,1001 is 10, 1002 is 10, 1003 is 10 and the return is happen means i have to show the error as 1000 is 10(product is available)
through error handling