create or replace trigger testT
AFTER INSERT OR UPDATE OR DELETE ON A
for each row
declare
-- local variables here
begin
IF INSERTING THEN
INSERT INTO b(a,b) VALUES(:NEW.a,:NEW.b);
ELSIF DELETING THEN
DELETE FROM b WHERE a=:OLD.a;
ELSE
UPDATE b SET b=:NEW.b WHERE a=:OLD.a;
END IF;
end testT;
SQL> desc a
Name Type Nullable Default Comments
---- ------------ -------- ------- --------
A VARCHAR2(20) Y
B VARCHAR2(20) Y
SQL> desc b;
Name Type Nullable Default Comments
---- ------------ -------- ------- --------
A VARCHAR2(20) Y
B VARCHAR2(20) Y
SQL> insert into a values(\'a\',\'b\');
1 row inserted
SQL> commit;
Commit complete
SQL> select * from b;
A B
-------------------- --------------------
a b
SQL> update a set b=\'c\' where a=\'a\';
1 row updated
SQL> commit;
Commit complete
SQL> select * from b;
A B
-------------------- --------------------
a c
SQL> delete from a where a=\'a\';
1 row deleted
SQL> commit;
Commit complete
SQL> select * from b;
A B
-------------------- --------------------
SQL>
