Basis Data II. Pertemuan Ke-9 dan ke-10 (Stored Procedure dan Trigger) Noor Ifada S1 T. Informatika - UTM (2012) 1

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1 Basis Data II Pertemuan Ke-9 dan ke-10 (Stored Procedure dan Trigger) Noor Ifada S1 T. Informatika - UTM (2012) 1

2 Sub Pokok Bahasan Stored Procedure vs Trigger Stored Procedure Trigger S1 T. Informatika - UTM (2012) 2

3 Stored Procedure vs Trigger Persamaan: Obyeknya dapat berupa TABEL, VIEW, dll Tersimpan di dalam System Catalog basisdata Terdiri dari penyataan SQL yang deklaratif (seperti CREATE, UPDATE, dan SELECT) dan prosedural (seperti IF-THEN-ELSE dan WHILE-DO) Perbedaan: Stored procedure diaktifkan sebagai suatu pernyataan oleh SQL editor, program, atau oleh stored procedure atau trigger lain Trigger diaktifkan hanya oleh RDBMS dalam suatu kondisi tertentu (ketika pernyataan INSERT, UPDATE, DELETE dieksekusi) S1 T. Informatika - UTM (2012) 3

4 STORED PROCEDURE Create Stored Procedure: <create procedure statement> ::= CREATE PROCEDURE <procedure name> ( [ <parameter list> ] ) <routine body> <parameter list> ::= <parameter specification> [, <parameter specification> ]... <parameter specification> ::= [ IN OUT INOUT ] <parameter> <data type> <routine body> ::= <begin-end block> <begin-end block> ::= [ <label> : ] <statement list> [ <label> ] <statement list> ::= { <body statement> ; }... <statement in body> ::= <declarative statement> <procedural statement> Aktivasi/pemanggilan Stored Procedure: <call statement> ::= CALL [ <database name>. ] <stored procedure name> ( [ <scalar expression> [, <scalar expression> ]... ] ) Menghapus Stored Procedure: <drop procedure statement> ::= DROP PROCEDURE [ IF EXISTS ] [ <database name>. ] <procedure name> S1 T. Informatika - UTM (2012) 4

5 Contoh Stored Procedure Contoh 1: Buatlah stored procedure untuk menghapus seluruh pertandingan yang pernah dimainkan oleh suatu pemain tertentu! CREATE PROCEDURE DELETE_MATCHES (IN P_PLAYERNO INTEGER) DELETE FROM MATCHES WHERE PLAYERNO = P_PLAYERNO; Contoh 2: Hapuslah seluruh pertandingan yang pernah dimainkan oleh pemain nomor 8 dengan penggunakan prosedur DELETE_MATCHES! CALL DELETE_MATCHES (8) S1 T. Informatika - UTM (2012) 5

6 Contoh Stored Procedure (contd-2) Contoh 3: Hapuslah pemain nomor 83 dari basisdata TENNIS. Akan tetapi jika pemain tersebut adalah kapten tim, maka pemain tidak boleh dihapus dari basisdata! Solusi PERTAMA: Eksekusi satu-per-satu Cek apakah pemain nomor 83 adalah kapten tim: SELECT COUNT(*) AS IS_CAPTAIN FROM TEAMS WHERE PLAYERNO = 83 Oleh karena pemain nomor 83 bukanlah kapten suatu tim, maka hapuslah semua data mengenai pemain tersebut: DELETE FROM MATCHES DELETE FROM COMMITTEE_MEMBERS DELETE FROM PENALTIES DELETE FROM PLAYERS S1 T. Informatika - UTM (2012) 6

7 Contoh Stored Procedure (contd-3) Solusi KEDUA: Dengan stored procedure (tanpa parameter) CREATE PROCEDURE DELETE_PLAYER_83() DECLARE NUMBER_OF_TEAMS INTEGER; SELECT COUNT(*) INTO NUMBER_OF_TEAMS FROM TEAMS IF NUMBER_OF_TEAMS = 0 THEN DELETE FROM MATCHES DELETE FROM COMMITTEE_MEMBERS DELETE FROM PENALTIES DELETE FROM PLAYERS IF; Aktivasi/pemanggilan stored procedure: CALL DELETE_PLAYER_83 Menghapus stored procedure: DROP PROCEDURE DELETE_PLAYER_83 S1 T. Informatika - UTM (2012) 7

8 Contoh Stored Procedure (contd-4) Solusi KETIGA: Stored procedure dengan parameter CREATE PROCEDURE DELETE_PLAYER (IN P_PLAYERNO INTEGER) DECLARE NUMBER_OF_TEAMS INTEGER; SELECT COUNT(*) INTO NUMBER_OF_TEAMS FROM TEAMS WHERE PLAYERNO = P_PLAYERNO; IF NUMBER_OF_TEAMS = 0 THEN DELETE FROM MATCHES WHERE PLAYERNO = P_PLAYERNO; DELETE FROM COMMITTEE_MEMBERS WHERE PLAYERNO = P_PLAYERNO; DELETE FROM PENALTIES WHERE PLAYERNO = P_PLAYERNO; DELETE FROM PLAYERS WHERE PLAYERNO = P_PLAYERNO; IF; Aktivasi/pemanggilan stored procedure: CALL DELETE_PLAYER(83) Menghapus stored procedure: DROP PROCEDURE DELETE_PLAYER S1 T. Informatika - UTM (2012) 8

9 TRIGGER Create Trigger: <create trigger statement> ::= CREATE [ <definer option> ] TRIGGER <trigger name> <trigger moment> <trigger event> <trigger action> <definer option> ::= DEFINER = { <user name> CURRENT_USER } <trigger moment> ::= BEFORE AFTER <trigger event> ::= { INSERT DELETE UPDATE } ON <table specification> FOR EACH ROW <trigger action> ::= <statement> Menghapus Stored Procedure: <drop trigger statement> ::= DROP TRIGGER [ <table name>. ] <trigger name> S1 T. Informatika - UTM (2012) 9

10 Contoh Trigger Contoh 1: Buatlah tabel CHANGES! CREATE TABLE CHANGES (USER CHAR(30) NOT NULL, CHA_TIME TIMESTAMP NOT NULL, CHA_PLAYERNO SMALLINT NOT NULL, CHA_TYPE CHAR(1) NOT NULL, CHA_PLAYERNO_NEW INTEGER, PRIMARY KEY (USER, CHA_TIME, CHA_PLAYERNO, CHA_TYPE)); Contoh 2: Buatlah trigger yang akan meng-update tabel CHANGES secara otomatis setiap kali ada penambahan baris baru di dalam tabel PLAYERS! CREATE TRIGGER INSERT_PLAYERS AFTER INSERT ON PLAYERS FOR EACH ROW INSERT INTO CHANGES (USER, CHA_TIME, CHA_PLAYERNO,CHA_TYPE, CHA_PLAYERNO_NEW) VALUES (USER, CURDATE(), NEW.PLAYERNO, 'I', NULL); S1 T. Informatika - UTM (2012) 10

11 Contoh Trigger (contd-2) Contoh 3: Trigger juga dapat memanggil stored procedure. Maka, trigger pada Contoh 2 dapat diubah/dipecah menjadi 2 bagian seperti berikut ini: CREATE PROCEDURE INSERT_CHANGE (IN CPNO INTEGER, IN CTYPE CHAR(1), IN CPNO_NEW INTEGER) INSERT INTO CHANGES (USER, CHA_TIME, CHA_PLAYERNO, CHA_TYPE, CHA_PLAYERNO_NEW) VALUES (USER, CURDATE(), CPNO, CTYPE, CPNO_NEW); CREATE TRIGGER INSERT_PLAYER AFTER INSERT ON PLAYERS FOR EACH ROW CALL INSERT_CHANGE(NEW.PLAYERNO, 'I', NULL); S1 T. Informatika - UTM (2012) 11

12 Contoh Trigger (contd-3) Contoh 4: Buatlah trigger yang meng-update tabel CHANGES setiap kali ada baris di dalam tabel PLAYERS yang dihapus! CREATE TRIGGER DELETE_PLAYER AFTER DELETE ON PLAYERS FOR EACH ROW CALL INSERT_CHANGE (OLD.PLAYERNO, 'D', NULL); Contoh 5: Buatlah trigger yang meng-update tabel CHANGES setiap kali ada baris di dalam tabel PLAYERS yang di-update! CREATE TRIGGER UPDATE_PLAYER AFTER UPDATE ON PLAYERS FOR EACH ROW CALL INSERT_CHANGES (NEW.PLAYERNO, 'U', OLD.PLAYERNO); S1 T. Informatika - UTM (2012) 12

13 Triggers: Integrity Constraints Contoh 6: Pastikan bahwa tahun kelahiran pemain adalah lebih kecil daripada tahun ketika ia bergabung di dalam klub! Solusi PERTAMA: Penggunaan Integrity Constraint ketika create tabel CREATE TABLE PLAYERS_Z (PLAYERNO SMALLINT NOT NULL, BIRTH_DATE DATE, JOINED SMALLINT NOT NULL, CHECK(YEAR(BIRTH_DATE) < JOINED)) Solusi KEDUA: Dengan Trigger CREATE TRIGGER BORN_VS_JOINED BEFORE INSERT, UPDATE ON PLAYERS_Z FOR EACH ROW IF YEAR(NEW.BIRTH_DATE) >= NEW.JOINED) THEN ROLLBACK WORK; IF; S1 T. Informatika - UTM (2012) 13

14 Keterangan lebih detail mengenai: Stored Procedure dan Trigger Cek MySQL 5.0 Reference Manual (Chapter 18. Stored Programs & Views) dan SQL for MySQL Developers (PART IV. Procedural Database Objects) S1 T. Informatika - UTM (2012) 14

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