inv-1
    p1-2

order-2
    pr1-1row------2nd-shipped
    pr1-2nd row----3rd





bill
    p1-3
serial no:
    p1-1st row- arrived
    p1-2nd row inv1 stutus-shipped
    p1-3rd row inv1   ordered




order3 
 pr1-1 ----p1-1st row-
  pr1-2
   pr1-3
    pr1-4


multiple row order_items+add clumn serial number
function:check:serial number available 
        check:order_items (serial number not attached yet)