My trigger compiles but does not work [closed]

I have a problem with the trigger to reduce stock. The trigger compiles me and everything but how much I insert data into my table detalle_venta, in the product table it does not reduce the amount.

These are my tables:

create table producto
(
    proId int primary key not null,
    prodNombre varchar(40),
    prodCant int,
    prodPrecio decimal(7,2)
 );
commit;

create table detalle_venta
(
    dvId int primary key not null,
    proId int,
    foreign key(proId) references producto(proId),
    venId int,
    foreign key(venId) references venta(venId),
    dvCantidad int,
    dvPrecioart decimal(7,2),
    dvTotal decimal(7,2)
);
commit;

create trigger ACTUALIZAR_STOCK_TRG
after insert or delete or update
on DETALLE_VENTA
for each row 
begin
if(inserting or updating)
then
UPDATE PRODUCTO
set PRODCANT = PRODCANT - :new.dvcantidad
where PROID = :new.DVID;
end if;
if(inserting or deleting)
then 
update PRODUCTO
set PRODCANT = PRODCANT + :new.dvcantidad
where PROID = :old.DVID;
end if;
end;