ACTIVE DATABASE AND TRIGGER2009 © Umi Laili Yuhana, S.Kom, M.Sc., Dini Adni, S.Kom, Nurul Fajrin, S.Kom, Wijayanti, S.Kom, Ridho Rahman, S.Kom

BDL Genap 2008

Teknik Informatika - ITS

Topik Minggu Ini

Pertemuan Ke-

Materi

1 PENDAHULUAN

Penjelasan Silabus Perkuliahan Review tentang basis data, data modelling

(cdm+pdm) Trend tentang database

2 ACTIVE DATABASE• Active dan passive database concept• Trigger

3 APLIKASI ACTIVE DATABASE• Integrity management• Derived data maintenance• Business rule• Penugasan tugas analisa case study dan

penerapan active database

Outline

Konsep pasive database dan active database

Model umum untuk active database dan trigger

Aplikasi-aplikasi untuk active database Desain dan isu implementasi untuk active

database Contoh statement-level active rule dalam

STARBURST, Oracle dan DB2 dan Chimera

Pasive Database

DB digunakan sebagai tempat penyimpan data (repositoris)

Database tidak bisa melakukan action tertentu ketika suatu event tertentu terjadi

Perintah (command) seperti query, update dan delete diekseskusi oleh database ketika di-request oleh pengguna atau program aplikasi

Active Database

DB dapat bereaksi dan memberikan respon tertentu ketika suatu kejadian terjadi

Merupakan sistem database yang didukung oleh fitur automatic execution pada saat kondisi tertentu atau kejadian tertentu terjadi

Menggunakan active rule (trigger) yang disebut dengan ECA rule.

ECA rule terdiri dari 3 komponen utama yaitu ECA (Event, Condition, and Action)

Model Umum untuk Active DB Event : kejadian-kejadian yang menjadi

pemicu (trigger), biasanya berupa operasi-operasi yang ekplisit ada dalam database atau dapat juga berupa temporal atau eksternal event

Condition: menentukan apakah rule action harus dieksekusi atau tidak

Action : tindakan yang dilakukan, biasanya berupa urutan statement SQL atau bisa juga berupa program eksternal yang dieksekusi secara otomatis (stored procedure)

Contoh aplikasi potensial dari active rule Notification

Monitoring system Enforce integrity constraints

GPA alert and course prerequisites Business rule

Salary of employee can’t exceed that of manager

Maintenance of derived data Maintain the derived attribute,

TOTAL_SAL

Desain dan isu implementasi untuk active database STARBURST

SYNTAXCREATE RULE <rule-name> ON <table-name>WHEN <triggering-operations>[IF <SQL-predicate>]THEN <SQL-statements>[PRECEDES <rule-names>][FOLLOWS <rule-names>] <triggering-operations> ::= INSERTED|DELETED|

UPDATED [(column-names)]

Desain dan isu implementasi untuk active database STARBURST

SEMANTICWhile the conflict set is not empty

1. select one rule R from the conflict set among those rules at highest priority; R’s state becomes untriggered

2. Evaluate the condition of R3. If the condition of R is TRUE, then execute

the action of R.

Contoh Active Rules Executions di Starburst

Database states:

 CREATE RULE SalaryControl ON EmpWHEN INSERTED, DELETED, UPDATED (Sal)IF (SELECT AVG (Sal) FROM Emp) > 100THEN UPDATE Emp

SET Sal = .9 * Sal

Employee Sal

Stefano 90

Patrick 90

Michael 110

Insert (Rick, 150)

Insert (John, 120)

Employee Sal

Stefano 81

Patrick 81

Michael 99

Rick 135

John 108

Desain dan isu implementasi untuk active database ORACLE

SYNTAXCREATE TRIGGER<trigger-name> {BEFORE|AFTER} <trigger-events> ON <table-

name>[[REFERENCING <references>]FOR EACH ROW[WHEN (<condition>)]]<PL/SQL BLOCK> <trigger-events> ::= INSERT|DELETE|UPDATE

[OF (column-names)]<reference> ::= OLD AS <old-value-tuple-name>|

NEW AS <new-value-tuple-name>

Desain dan isu implementasi untuk active database ORACLE

SEMANTIC1. Execute the statement-level before triggers2. For each row in the target table :3. Perform statement-level referential integrity

and assertion checkinga. Execute the row-level before-triggersb. Perform the modification of the row and row-level

referential integrity and assertion checkingc. Execute the row-level after-triggers

4. Execute the statement-level after-triggers

Desain dan isu implementasi untuk active database TIPE TRIGGER PADA ORACLE

STATEMENT TRIGGER Dieksekusi hanya SATU KALI sebelum atau

setelah (BEFORE/AFTER) suatu kejadian yang berupa INSERT, UPDATE dan DELETE

ROW TRIGGER Dieksekusi SATU KALI untuk setiap baris (FOR

EACH ROW) sebelum atau setelah (BEFORE/AFTER) suatu kejadian yang berupa INSERT, UPDATE dan DELETE

Contoh active rule execution di ORACLE(Statement TRIGGER)

CREATE TRIGGER LogUserNilaiAFTER INSERT ON FRSBEGIN

INSERT INTO LogNilai VALUES (user, sysdate,‘INSERT’);

END;

NRP NILAI

5102100180 A

NM TGL KET

ARI 3/2/09 UPDATE

INSERT INTO FRS (‘5102100020’,’B’)

NRP NILAI

5102100180 A

5102100020 B

NM TGL KET

ARI 3/2/09 UPDATE

ANI 7/2/09 INSERT

Contoh active rule execution di ORACLE (Row TRIGGER)CREATE TRIGGER ReorderAFTER UPDATE of PartOnHand ON InventoryWHEN (:new.PartOnHand<:New.ReorderPoint)FOR EACH ROWDECLARE NUMBER X;BEGINSELECT COUNT (*) INTO X FROM PendingOrders WHERE Part=:new.Part;IF X=0THENINSERT INTO PendingOrders VALUES (:new.Part,:new.OrderQuantity,SYSDATE)END IF;END;

Contoh active rule execution di ORACLE (Row TRIGGER)

Part PartOnHand

ReorderPoint ReorderQuantity

1 200 150 100

2 780 500 200

3 450 400 120

TABEL INVENTORY

Part

OrderQuantity

TGL

TABLE PendingOrders

UPDATE INVENTORY SET PartOnHand= PartOnHand-70 WHERE Part=1

Part

PartOnHand

ReorderPoint ReorderQuantity

1 130 150 100

2 780 500 200

3 450 400 120

Part

OrderQuantity

TGL

1 100 3/2/2009

TABLE PendingOrders

TABEL INVENTORY

Contoh active rule execution di ORACLE (Row TRIGGER)

Part

PartOnHand

ReorderPoint

ReorderQuantity

1 200 150 100

2 780 500 200

3 450 400 120

TABEL INVENTORY

Part

OrderQuantity

TGL

TABLE PendingOrders

Part PartOnHand

ReorderPoint

ReorderQuantity

1 140 150 100

2 720 500 200

3 390 400 120

Part OrderQuantity

TGL

1 100 3/2/2009

3 120 3/2/2009

TABLE PendingOrders

TABEL INVENTORY

UPDATE INVENTORY SET PartOnHand= PartOnHand-60 WHERE Part>=1

Desain dan isu implementasi untuk active database MUTATING TABLE

tabel yang sedang dimodifikasi menggunakan statemen UPDATE, DELETE, atau INSERT,

table yang mungkin harus diupdate karena efek dari deklarasi referential integrity constraint seperti DELETE CASCADE

Contoh active rule execution di ORACLE (Mutating Table) ORACLE

MUTATING TABLECREATE OR REPLACE TRIGGER mhs_count

AFTER DELETE ON mhs

FOR EACH ROW

DECLARE n INTEGER;

BEGIN

SELECT COUNT(*) INTO n FROM mhs;

DBMS_OUTPUT.PUT_LINE(' Jumlah mhs = ' || n ||' orang.');

END;

Desain dan isu implementasi untuk active database DB2

SYNTAXCREATE TRIGGER<trigger-name> {BEFORE|AFTER} <trigger-event> ON <table-name>[REFERENCING <references>]FOR EACH {ROW|STATEMENT}WHEN (<SQL-condition>)<SQL procedure-statements><trigger-events> ::= INSERT|DELETE|UPDATE

[OF (column-names)]<reference> ::= OLD AS <old-value-tuple-name>|

NEW AS <new-value-tuple-name>|OLD_TABLE AS <old-value-table-name>|NEW_TABLE AS <new-value-table-name>

Desain dan isu implementasi untuk active database DB2

SEMANTIC1. Suspend the execution of A and save its working storage

on a stack2. Compute transition values (OLD and NEW) relative to

event E3. Consider and execute all before-triggers relative to event

E, possibly changing the NEW transition values4. Apply NEW transition value to the database, thus making

the state change associated to event E effective5. Consider and execute all after-triggers relative to event E.

if any of them contains an action Ai that activates other triggers then invoke this processing procedure recursively for Ai

6. Pop from the stack the working storage for A and continue its evaluation

Desain dan isu implementasi untuk active database DB2

SEMANTIC (revised step 4)4. Apply NEW transition values to the database, thus

making the state change associated to event E effective. For each integrity constraint IC violated by the current state, consider the action Aj that compensates the integrity constraint IC.

a. Compute the transition values (OLD and NEW) relative to Aj

b. Execute the before-triggers relative to Aj, possibly changing the NEW transition values

c. Apply NEW transition values to the database, thus making the state change associated to Aj effective

d. Push all after-triggers relative to action Aj into queue of suspended triggers

Contoh Active Rules Executions di DB2 Tabel: Part, Distributor, Audit Part, DEFAULT = ‘HDD’

Part Distributor

FOREIGN KEY (Supplier) REFERENCES Distributor ON DELETE SET DEFAULT

Distributor City State

Jones Palo Alto California

Taylor Minneapolis

Minnesota

HDD Atlanta Georgia

PartNum Supplier Cost

1 Jones 150

2 Taylor 500

3 HDD 400

4 Jones 800

Contoh Active Rules Executions di DB2 SUPPLIER RULE

*trigger di atas tidak menangani inputan data yg bernilai NULL pada Supplier

CREATE TRIGGER OneSupplier BEFORE UPDATE OF Supplier ON PartREFERENCING NEW AS NFOR EACH ROWWHEN (N.Supplier IS NULL) SIGNAL SQLSTATE ‘70005’ (‘Cannot change supplier into NULL’)

Contoh Active Rules Executions di DB2 AUDIT RULE

CREATE TRIGGER AuditSupplier AFTER UPDATE OF Supplier ON PartREFERENCING OLD_TABLE AS OTFOR EACH STATEMENT INSERT INTO Audit VALUES (USER, CURRENT_DATE, (SELECT COUNT(*) FROM OT)

user Bill melakukan transaksi pada October 10, 1996:

DELETE FROM DistributorWHERE State = ‘California’

User CurrentDate UpdatedTuples

Bill 1996-10-10 2

Audit

Desain dan isu implementasi untuk active database CHIMERA

SYNTAXDEFINE TRIGGER<trigger-name> [FOR <class-name>]EVENTS < triggering-events>CONDITION <formula>ACTIONS <procedural-expression>[{BEFORE|AFTER} <trigger-names>]END <triggering-event> ::= CREATE|DELETE|MODIFY

[<attr-name>]<option> ::= [<consumption-opt>][<execution-

opt>]<consumption-opt> ::= event-consuming|event-preserving<execution-opt> ::= deferred|immediate

Desain dan isu implementasi untuk active database CHIMERA

SEMANTICWhile the conflict set is not empty do:

1. select one trigger T from the conflict set among those rules at highest priority; T’s state becomes untriggered

2. Evaluate the condition of T3. If the condition of T is TRUE, then execute

the action of T

Contoh Active Rule Execution di CHIMERA Initial Schema

Employee

Name: string

Salary: integer

Mgr: Employee

SpecialEmp

Name: string

Department

Name: string

Employees: set-of(Employee)

Class Employee:

{(o1,’john’,3500,o2),

(o2,’tom’,4500,null),

(o3,’bob’,4300,o2)}

Class SpecialEmp:

{ }

Class Department:

{(o4,’toys’,{o1,o2,o3}) }

Contoh Active Rule Execution di CHIMERA

Transaksi

define trigger AdjustSalary for Employeeevents create, modify(Salary)condition Self.Salary > Self.Mgr.Salaryactions modify (Employee.Salary, Self, Self.Mgr.Salary)

end;begin transaction;select(X where employee(X), X.name=‘tom’),

modify(Employee.Salary,X,5000);select(X where employee(X),X.name=‘john’),

modify(Employee.Salary,X,5300);commit;

(o1,’john’,5000)

Contoh Soal Trigger

Ketika data dosen dihapus maka set nipwali mahasiswa menjadi null

Syntax :create trigger tr1before delete on dosenfor each rowbegin update mhs m set m.nipwali=null where

m.nipwali= :old.nip; end;