create or replace procedure foo
  (
   p_emp_id in transaction.emp_id%type,
   p_cust_id in transaction.cust_id%type,
   p_tranpaymenttype in transaction.tranpaymenttype%type,
   p_inv_id_input1 in inventory.inv_id%type,
   p_inv_id_input2 in inventory.inv_id%type,
   p_inv_id_input3 in inventory.inv_id%type
  )
as
  v_trans_total  catalog.cata_rentalprice%type;
begin
  insert into transaction 
  (tran_id, emp_id, cust_id, tran_datetime, tranpaymenttype) 
  values 
  (trans_id.nextval, p_emp_id, p_cust_id, sysdate, p_tranpaymenttype);
 
  update inventory 
     set inv_quantityinstock = inv_quantityinstock - 1
   where inv_id in (p_inv_id_input1, p_inv_id_input2, p_inv_id_input3);
 
  select sum(cata_rentalprice)
    into v_trans_total
    from catalog
   where inv_id in (p_inv_id_input1, p_inv_id_input2, p_inv_id_input3);
 
  -- do something with v_trans_total (display, return, etc.)
 
exception
  when others then
    htp.p('PROC_TRANS_INV: ' || sqlcode || ' ' || sqlerrm);
    htp.br;
end;
/