Two table synchronization triggers in Oracle

/* Create Table */
Create table A_ybl (

Y INTEGER not null,

B VARCHAR (30) not null,

L VARCHAR (20) not null

);
/* Create A backup table for table */

Create table A_ybl2 (

Y INTEGER not null,

B VARCHAR (30) not null,

L VARCHAR (20) not null

);
Create or replace trigger test
After insert or update or delete on A_ybl for each row

Declare
Error_exception exception,
Errno integer,
Errmsg char (20 ),
Dummy integer,
Found boolean;

Begin
If inserting then
Insert into A_ybl2 values (: NEW. y,: NEW. B,: NEW. l );
Elsif updating then
Update A_ybl2 set y =: NEW. y,
B =: NEW. B,
L =: NEW. l
Where id: =: OLD. y;
Elsif deleting then
Delete from A_ybl2 where y =: old. id;
End if;
 
Exception
 
When error_exception then
Raise_application_error (errno, errmsg );
End;