This document discusses Oracle database triggers. It defines triggers as stored procedures that are activated when certain conditions occur, such as when a data manipulation language (DML) statement is executed. Triggers can be used at the table, schema, or database level. Examples are provided that demonstrate using triggers to log changes to employee salaries or to validate data. Statement-level and row-level triggers are described. Triggers can call stored procedures, including Java procedures. The document also covers creating, viewing, disabling, and dropping triggers.

1. ORACLE Trigger
Hasan Dwi Cahyono

2. Overviews
 Pengertian Trigger
 Schema Trigger
 Aplikasi Trigger
Perancangan Basis Data - Trigger2

3. Pengertian Trigger
 Database triggers adalah prosedur yang tersimpan
dalam database dan di aktifkan ketika kondisi
tertentu terjadi
 Dapat digunakan untuk menambah kapabilitas agar
database mampu dikostumasi secara sistematis.
 Sebagai contoh, membuat Trigger yang dapat
membatasi perintah DML tertentu pada sebuah tabel
dan mengijinkan perintah tertentu pada waktu
tertentu juga.
Perancangan Basis Data - Trigger3

4. Pengertian Trigger (Lanjutan)
 Database triggers dapat digunakan dalam sebuah
table, schema, atau database.
 Cara memicunya ketika:
 Perintah DML dieksekusi (INSERT, UPDATE, DELETE)
terhadap tabel tertentu.
 DDL tertentu dieksekusi (contohnya:
ALTER, CREATE, DROP) pada sebuah objek pada
database atau schema.
 Event tertentu terjadi pada database
(contohnya: STARTUP, SHUTDOWN, SERVERERROR)
Perancangan Basis Data - Trigger4

5. Schema Trigger: Create Trigger
CREATE [ OR REPLACE ] TRIGGER [ schema. ]trigger
{ BEFORE | AFTER | INSTEAD OF }
{ dml_event_clause
| { ddl_event [ OR ddl_event ]...
| database_event [ OR database_event ]...
} ON { [ schema. ]SCHEMA
| DATABASE
}
}
[ WHEN (condition) ]
{ pl/sql_block | call_procedure_statement } ;
Perancangan Basis Data - Trigger5

6. Schema Trigger: Create Trigger (Lanj.)
Perancangan Basis Data - Trigger6

7. Schema Trigger: DML Event Clause
{ DELETE | INSERT | UPDATE
[ OF column [, column ]... ]
}
[ OR { DELETE | INSERT | UPDATE
[ OF column [, column]... ]
}
]...
ON { [ schema. ]table
| [ NESTED TABLE nested_table_column OF ]
[ schema. ] view
}
[ referencing_clause ]
[ FOR EACH ROW ]
Perancangan Basis Data - Trigger7

8. Schema Trigger: DML Event Clause (Lanj.)
Perancangan Basis Data - Trigger8

9. Schema Trigger: Referencing Clause
REFERENCING
{ OLD [ AS ] old
| NEW [ AS ] new
| PARENT [ AS ] parent }
[ OLD [ AS ] old
| NEW [ AS ] new
| PARENT [ AS ] parent ]...
Perancangan Basis Data - Trigger9

10. Schema Trigger: Referencing Clause
Perancangan Basis Data - Trigger10

11. Options: Event-nya
 AFTER atau bisa juga BEFORE.
 UPDATE ON bisa juga DELETE ON atau INSERT
ON.
 Dan UPDATE ON dapat juga UPDATE …OF… ON
Perancangan Basis Data - Trigger11

12. Aplikasi Trigger (Buat tabel contoh)
CREATE TABLE Project_tab (
Prj_level NUMBER,
Projno NUMBER,
Resp_dept NUMBER
);
CREATE TABLE Emp_tab (
Empno NUMBER NOT NULL,
Ename VARCHAR2(10),
Job VARCHAR2(9),
Mgr NUMBER(4),
Hiredate DATE,
Sal NUMBER(7,2),
Comm NUMBER(7,2),
Deptno NUMBER(2) NOT NULL
);
CREATE TABLE Dept_tab (
Deptno NUMBER(2) NOT NULL,
Dname VARCHAR2(14),
Loc VARCHAR2(13),
Mgr_no NUMBER,
Dept_type NUMBER
);
Perancangan Basis Data - Trigger12

13. Contoh Trigger Pada Tabel
 Terjadi Ketika Insert, Update, dan Delete
CREATE OR REPLACE TRIGGER Print_salary_changes
BEFORE DELETE OR INSERT OR UPDATE ON Emp_tab
FOR EACH ROW
WHEN (new.Empno > 0)
DECLARE
sal_diff number;
BEGIN
sal_diff := :new.sal - :old.sal;
dbms_output.put('Old salary: ' || :old.sal);
dbms_output.put(' New salary: ' || :new.sal);
dbms_output.put_line(' Difference ' || sal_diff);
END; /
 Lakukan Perintah:
UPDATE Emp_tab SET sal = sal + 500.00 WHERE deptno = 10;
 Apa yang terjadi?
Perancangan Basis Data - Trigger13

14. Contoh Trigger Pada View
CREATE OR REPLACE VIEW manager_info AS
SELECT e.ename, e.empno, d.dept_type,
d.deptno, p.prj_level, p.projno
FROM Emp_tab e, Dept_tab d, Project_tab p
WHERE e.empno = d.mgr_no
AND d.deptno = p.resp_dept;
Perancangan Basis Data - Trigger14

15. Contoh Trigger Pada View (Lanjutan)
CREATE OR REPLACE TRIGGER
manager_info_insert
INSTEAD OF INSERT ON manager_info
REFERENCING NEW AS n
-- new manager information
FOR EACH ROW
DECLARE
rowcnt number;
BEGIN
SELECT COUNT(*) INTO rowcnt
FROM Emp_tab WHERE empno = :n.empno;
IF rowcnt = 0 THEN
INSERT INTO Emp_tab (empno,ename)
VALUES (:n.empno, :n.ename);
ELSE
UPDATE Emp_tab
SET Emp_tab.ename = :n.ename
WHERE Emp_tab.empno = :n.empno;
END IF;
SELECT COUNT(*) INTO rowcnt
FROM Dept_tab WHERE deptno = :n.deptno;
IF rowcnt = 0 THEN
INSERT INTO Dept_tab (deptno, dept_type)
VALUES(:n.deptno, :n.dept_type);
ELSE
UPDATE Dept_tab
SET Dept_tab.dept_type = :n.dept_type
WHERE Dept_tab.deptno = :n.deptno;
END IF;
SELECT COUNT(*) INTO rowcnt
FROM Project_tab
WHERE Project_tab.projno = :n.projno;
IF rowcnt = 0 THEN
INSERT INTO Project_tab (projno, prj_level)
VALUES(:n.projno, :n.prj_level);
ELSE
UPDATE Project_tab
SET Project_tab.prj_level = :n.prj_level
WHERE Project_tab.projno = :n.projno;
END IF;
END;
Perancangan Basis Data - Trigger15

16. Contoh Trigger Pada View (Lanjutan)
Perancangan Basis Data - Trigger16
 Lakukan Perintah:
INSERT INTO manager_info
(ename, empno, dept_type, deptno,
prj_level, projno)
VALUES(‘Andi’, 101, 1, 1, 1,1);
 Apa yang terjadi?

17. Firing Triggers Sekali atau Berkali-kali
(FOR EACH ROW Option)
CREATE TABLE Emp_log (
Emp_id NUMBER,
Log_date DATE,
New_salary NUMBER,
Action VARCHAR2(20)
);
CREATE OR REPLACE TRIGGER
Log_salary_increase
AFTER UPDATE ON Emp_tab
FOR EACH ROW
WHEN (new.Sal > 1000)
BEGIN
INSERT INTO Emp_log
(Emp_id, Log_date,
New_salary, Action)
VALUES (:new.Empno,
SYSDATE, :new.SAL,
'NEW SAL');
END;
Lakukan perintah:
UPDATE Emp_tab SET Sal = Sal + 1000.0 WHERE Deptno = 20;
Perancangan Basis Data - Trigger17

18. Trigger Ini Hanya Dijalankan Sekali
CREATE OR REPLACE TRIGGER Log_emp_update
AFTER UPDATE ON Emp_tab
BEGIN
INSERT INTO Emp_log (Log_date, Action)
VALUES (SYSDATE,
'Emp_tab COMMISSIONS CHANGED');
END;
Perancangan Basis Data - Trigger18

19. Memanggil Java Procedure dari Trigger
CREATE OR REPLACE PROCEDURE Before_delete (Id IN NUMBER, Ename
VARCHAR2)
IS language Java
name 'thjvTriggers.beforeDelete (oracle.sql.NUMBER,
oracle.sql.CHAR)';
CREATE OR REPLACE TRIGGER Pre_del_trigger
BEFORE DELETE ON Tab
FOR EACH ROW
CALL Before_delete (:old.Id, :old.Ename)
/
Perancangan Basis Data - Trigger19

20. thjvTriggers.java
import java.sql.*
import java.io.*
import oracle.sql.*
import oracle.oracore.*
public class thjvTriggers {
public state void beforeDelete (NUMBER old_id, CHAR old_name)
Throws SQLException, CoreException
{
Connection conn = JDBCConnection.defaultConnection();
Statement stmt = conn.CreateStatement();
String sql = “insert into logtab values (“ +
old_id.intValue() + ", '“ +
old_ename.toString() + ", BEFORE DELETE');
stmt.executeUpdate (sql);
stmt.close();
return;
}
}
Perancangan Basis Data - Trigger20

21. Latihan
 Menggunakan tabel Penjual(nama, minuman, harga) dan sebuah
relasi unary, simpan daftar penjual yang menaikkan harga sebesar
Rp.1000.
 Misal relasi Unary-nya kepada: KumpulanPenjual(nama).
CREATE TABLE Penjual(
minuman VARCHAR(10),
nama VARCHAR(13),
harga FLOAT
);
CREATE TABLE KumpulanPenjual(
nama VARCHAR(13)
);
Perancangan Basis Data - Trigger21

22. Trigger
CREATE OR REPLACE TRIGGER PriceTrig
AFTER UPDATE OF price ON Penjual
FOR EACH ROW
WHEN (new.harga > old.harga + 1000)
BEGIN
INSERT INTO KumpulanPenjual
VALUES(:new.nama);
END;
/
Perancangan Basis Data - Trigger22

23. Contoh Lainnya:
CREATE TABLE emp (
empno INT,
ename VARCHAR(30),
deptno INT,
sal FLOAT,
comm FLOAT
);
CREATE OR REPLACE TRIGGER emp_comm_trig
BEFORE INSERT ON emp
FOR EACH ROW
BEGIN
IF :NEW.deptno = 30 THEN
:NEW.comm := :NEW.sal * .4;
END IF;
END;
/
Perancangan Basis Data - Trigger23

24. Latihan:
INSERT INTO emp VALUES (9005,'ROBERS',30,
3000,NULL);
INSERT INTO emp VALUES (9006,'ALLEN',30, 4500,NULL);
SELECT * FROM emp WHERE empno IN (9005, 9006);
EMPNO ENAME DEPTNO SAL COMM
-----------------------------------
9005 ROBERS 30 3000 1200
9006 ALLEN 30 4500 1800
Perancangan Basis Data - Trigger24

25. Trigger:Membatalkan Perintah dengan Error
 Trigger dapat digunakan untuk melukan pengecekan contrain.
 Perintah-nya: RAISE_APPLICATION_ERROR.
 Perintah yang mengaktifkan Trigger (insert, update, atau delete) akan
dibatalkan.
 Contohnya, perintah berikut ini memaksa nilai input harus Person.age >= 0:
CREATE TABLE Person (age INT);
CREATE TRIGGER PersonCheckAge
AFTER INSERT OR UPDATE OF age ON Person
FOR EACH ROW
BEGIN
IF (:new.age < 0) THEN
RAISE_APPLICATION_ERROR(-20000, 'no negative age allowed');
END IF;
END;
/
Perancangan Basis Data - Trigger25

26. Statement-Level Trigger
 Ketika operasi insert, update, atau delete operation
terjadi pada tabel emp, sebuah record akan
ditambahkan ke tabel empauditlog yang mencatat date,
user, dan action.
 Sebelumnya, buat tabel empauditlog table:
CREATE TABLE empauditlog (
audit_date DATE,
audit_user VARCHAR2(20),
audit_desc VARCHAR2(20)
);
Perancangan Basis Data - Trigger26

27. Trigger
CREATE OR REPLACE TRIGGER emp_audit_trig
AFTER INSERT OR UPDATE OR DELETE ON emp
DECLARE
v_action VARCHAR2(20);
BEGIN
IF INSERTING THEN
v_action := 'Added employee(s)';
ELSEIF UPDATING THEN
v_action := 'Updated employee(s)';
ELSEIF DELETING THEN
v_action := 'Deleted employee(s)';
END IF;
INSERT INTO empauditlog
VALUES (SYSDATE, USER, v_action);
END;
/
Perancangan Basis Data - Trigger27

28. Sekarang jalankan:
INSERT INTO emp (empno, ename, deptno) VALUES (9001,'SMITH',50);
INSERT INTO emp (empno, ename, deptno) VALUES (9002,'JONES',50);
UPDATE emp
SET ename = 'SMITH BROWN'
WHERE empno=9001;
DELETE FROM emp WHERE empno IN (9001, 9002);
SELECT TO_CHAR(AUDIT_DATE,'DD-MON-YY HH24:MI:SS') AS "AUDIT DATE",
audit_user, audit_desc
FROM empauditlog
ORDER BY 1 ASC;
AUDIT DATE AUDIT_USER AUDIT_DESC
------------------ -------------------- --------------------
08-FEB-08 09:43:02 THOMO Added employee(s)
08-FEB-08 09:43:02 THOMO Deleted employee(s)
08-FEB-08 09:43:02 THOMO Updated employee(s)
08-FEB-08 09:43:02 THOMO Added employee(s)
Perancangan Basis Data - Trigger28

29. Hal-hal Lain dalam Trigger
 Viewing Defined Triggers
 Untuk melihat Trigger yang tersimpan, gunakan perintah:
SELECT *
FROM USER_TRIGGERS[/DBA_TRIGGERS ]
WHERE TABLE_NAME = ‘MY_TABLE’;
 Melihat isi (code) Trigger:
SELECT text
FROM user_source
WHERE name = 'PRICETRIG'
ORDER BY line;
 Menghapus Triggers
DROP TRIGGER <trigger_name>;
 Disabling atau Enabling Triggers
ALTER TRIGGER <trigger_name>
{DISABLE|ENABLE};
Harus
UpperCase?
Perancangan Basis Data - Trigger29

30. Sumber:
Perancangan Basis Data - Trigger30
 Oracle.com
 http://webhome.cs.uvic.ca/~thomo/courses/csc370S
pring2009/triggers.ppt