Question

EDIT: Please disregard, I fixed it by disabling and then re-enabling the trigger. I don’t quite know why or how this fixed it as I never disabled it in the first place. Thanks all.

This trigger is meant to control the order of order_status values. So an order with a status “Dispatched” cannot become “Ready for Dispatch”, or an order with the value “Delivered” cannot become “Dispatched” etc.

It used to work fine, but today I converted the order table into an object table (well, dropped it and made a type etc) and since then it’s not worked. Constraints work fine, just not this trigger. It compiles without an issue but it simply never catches the fault. If anyone could help me here I’d appreciate it.

CREATE OR REPLACE TRIGGER Check_Order_Status  
BEFORE INSERT OR UPDATE ON Customer_Order 
for each row

BEGIN 

IF (:new.order_status='Processed' AND :old.order_status='Delivered'
 OR :new.order_status='Processed' AND :old.order_status='Dispatched' 
 OR :new.order_status='Dispatched' AND :old.order_status='Delivered' 
 OR :new.order_status='Delayed' AND :old.order_status='Delivered' 
 OR  :new.order_status='Ready for Dispatch' AND :old.order_status='Dispatched' 
 OR :new.order_status='Ready for Dispatch' AND :old.order_status='Delivered' 
 OR :new.order_status='Dispatched' AND :old.order_status IS NULL ) 
then  
 RAISE_APPLICATION_ERROR(-20103, 'There has been an issue with the order update or insert.');
ELSE
 dbms_output.put('Order Status of ' || :old.order_no || ' is now ' || :new.order_status);
END IF;

END; 
. 
run

Answer 1

Here is a minimalistic implementation of your scenario:

SQL> create or replace type order_rec as object
    (order_no number
     , order_status varchar2(30)
     , input_date date
     , ship_date date )
/
  2    3    4    5    6
Type created.

SQL>
SQL> create table Customer_Order of order_rec
/

  2
Table created.

SQL>

and your trigger compiles. So far, so good.

SQL> CREATE OR REPLACE TRIGGER Check_Order_Status
BEFORE INSERT OR UPDATE ON Customer_Order
for each row

BEGIN

IF (:new.order_status='Processed' AND :old.order_status='Delivered'
 OR :new.order_status='Processed' AND :old.order_status='Dispatched'
 OR :new.order_status='Dispatched' AND :old.order_status='Delivered'
 OR :new.order_status='Delayed' AND :old.order_status='Delivered'
 OR  :new.order_status='Ready for Dispatch' AND :old.order_status='Dispatched'
 OR :new.order_status='Ready for Dispatch' AND :old.order_status='Delivered'
 OR :new.order_status='Dispatched' AND :old.order_status IS NULL )
then
 RAISE_APPLICATION_ERROR(-20103, 'There has been an issue with the order update or insert.');
ELSE
 dbms_output.put('Order Status of ' || :old.order_no || ' is now ' || :new.order_status);
END IF;

END;   2    3    4    5    6    7    8    9   10   11   12   13   14   15   16   17   18   19   20
 21  /

Trigger created.

SQL>

Let’s create a row:

SQL> set serveroutput on

insert into customer_order values ( order_rec (1, 'New', sysdate, null))
/

SQL> SQL>   2
1 row created.

SQL>

update customer_order
set order_status = 'Dispatched'
where order_no = 1
/
SQL>   2    3    4
1 row updated.

SQL>

Hmmm, it’s a bit silent. Let’s poke it:

SQL> update customer_order
set order_status = 'Processed'
where order_no = 1
/
  2    3    4  update customer_order
       *
ERROR at line 1:
ORA-20103: There has been an issue with the order update or insert.
ORA-06512: at "APC.CHECK_ORDER_STATUS", line 11
ORA-04088: error during execution of trigger 'APC.CHECK_ORDER_STATUS'


SQL>

Your trigger works, for me at least. So why aren’t we seeing the DBMS_OUTPUT.PUT_LINE() calls ? Don’t know, but I would guess it’s probably a bug.

---

Incidentally, you should extract that logic from the trigger and put it in a member function on the object. An object is a set of data and a set of related behaviours. Status validation is definitely a behaviour, so it is even more wrong to have such a trigger on an object table than it was on a normal table.