Hi
Trigger code to add and minus stock from inventory


==========================add stock===========================
 create or replace trigger TRIG_STOCK2
 after insert or update on purchase
 for each row
 begin
 update inventory
 set stock=stock+:new.qty
 where id=:new.id;
 end;

====================Insert new stock & add previous stock======================
 create or replace trigger TRIG_STOCK2
 after insert or update on purchase
 for each row
 begin
 IF inserting then
 insert into inventory
 values(:new.id,:new.qty,:new.unit_price);
 ELSIF INSERTING THEN
 update inventory
 set stock=stock+:new.qty
 where id=:new.id;
 commit;
END IF;
 end;


========================minus stock===========================

 create or replace trigger TRIG_STOCK
 after insert or update on Sales
 for each row
 begin
 update inventory
 set stock=stock-:new.qty
 where id=:new.id;
 end;
==============================================================