laundry 28/10/2019

jualh-> tglbayar -> null (backup)
bayar_before_insert trigger

#insert
BEGIN
update jualh set bayar = bayar + new.jumlah, tglbayar = CURRENT_TIMESTAMP() where idjualh = new.idjualh;
END

#delete
BEGIN
update jualh set bayar = bayar - old.jumlah, tglbayar = null where idjualh = old.idjualh;
END