Stored Procedures, Function, Trigger, Dynamic SQL, Cursor. Introduction SMART DATABASE

Transkripsi

1 Stored Procedures, Function, Trigger, Dynamic SQL, Cursor Introduction SMART DATABASE

2 Apa Itu Smart Database?? Database yang menyimpan bisnis logic Database yang konsisten Database yang smart Database yang bukan hanya sekedar menyimpan data, tetapi dapat menjalankan bisnis logic dan dapat menjaga konsistensi data, sehingga dapat bekerja sebagai database yang smart

3 3-Tier Architecture

4 Object-Object Smart Database Stored Procedures Function Trigger Dynamic SQL Cursor

5 Apakah STORED PROCEDURES itu? STORED PROCEDURES Perintah SQL yang disimpan pada Database

6 a. Eksekusi yang sudah dikompilasi. b. Mengurangi trafik client/server. c. Efisiensi penggunaan code dan abtraksi pemrograman. d. Meningkatkan control keamanan pengguna. Keuntungan Menggunakan STORED PROCEDURES

7 Stored Procedures Syntax CREATE PROC[EDURE][schema.] procedure [ [schema.] data_type } [VARYING ] [ = default ] [ OUT[PUT] ] ] [,...n ] [WITH Option [,...n ]] AS { sql_statement [;][...n ] EXTERNAL NAME assembly.class.method } [;] ALTER PROCEDURE EXEC Execute Procedure DROP PROCEDURE

8 STORED PROCEDURES Samples (1) CREATE PROCEDURE [dbo].[getproducts] AS SELECT ProductID, ProductName FROM Products EXEC GetProducts

9 STORED PROCEDURES Samples (2) CREATE PROCEDURE INT OUTPUT AS SELECT Ord.EmployeeID, SummSales = SUM(OrDet.UnitPrice * OrDet.Quantity) FROM Orders AS Ord JOIN [Order Details] AS OrDet ON (Ord.OrderID = OrDet.OrderID) GROUP BY Ord.EmployeeID ORDER BY Ord.EmployeeID = MAX(Quantity) FROM [Order Details] RETURN (SELECT SUM(Quantity) FROM [Order Details])

10 STORED PROCEDURES Samples (2) INT INT = OUTPUT PRINT 'The size of the largest single order was: ' + PRINT 'The sum of the quantities ordered was: ' +

11 STORED PROCEDURES Samples (3) CREATE PROCEDURE nvarchar(5) AS SELECT orderid,customerid,orderdate FROM Orders WHERE EXEC

12 Apakah FUNCTION itu? FUNCTION Kumpulan query yang disimpan menjadi satu

13 a. Penggunaan kembali code, sehingga mengurangi waktu pembuatan. b. Menyembunyikan detail SQL. c. Tersentralisasi, sehingga memudahkan jika bisnis logic mengalami perubahan. Keuntungan Menggunakan FUNCTION

14 Function adalah subprogram yang harus mengembalikan nilai (menggunakan keyword RETURN) Function digunakan pada perintah SELECT, tetapi stored procedures tidak dapat digunakan didalam perintah SELECT. Function hanya mempunyai parameter IN, sedangkan stored procedures dapat terdiri atas parameter OUT atau INOUT Perbedaan STORED PROCEDURES dan FUNCTION Stored Procedure dapat mengembalikan banyak nilai menggunakan parameter OUT, atau tidak mengembalikan nilai sama sekali.

15 Function Syntax CREATE FUNCTION [schema.] function ( [@parameter [ AS ][type_schema.] parameter_data_type [= default ] [,...n ] ]) RETURNS return_clause... [;] ALTER FUNCTION DROP FUNCTION

16 Ada 3 tipe User-Defined Functions : 1. Scalar 2. Inline Table-Valued 3. Multi-Statement Table-Valued Tipe Function

17 FUNCTION Samples (1) - Scalar CREATE FUNCTION WhichContinent (@Country nvarchar(15)) RETURNS varchar(30) AS BEGIN varchar(30) = when 'Argentina' then 'South America' when 'Belgium' then 'Europe' when 'Brazil' then 'South America' when 'Canada' then 'North America' when 'Denmark' then 'Europe' when 'Finland' then 'Europe' when 'France' then 'Europe' else 'Unknown' end END

18 FUNCTION Samples (1) - Scalar PRINT dbo.whichcontinent('usa') SELECT dbo.whichcontinent(customers.country), customers.* FROM customers

19 FUNCTION Samples (2) Inline Table Valued CREATE FUNCTION CustomersByContinent varchar(30)) RETURNS TABLE AS RETURN SELECT dbo.whichcontinent(customers.country) as continent, customers.* FROM customers WHERE dbo.whichcontinent(customers.country)

20 FUNCTION Samples (2) Inline Table Valued SELECT * FROM CustomersbyContinent('North America') SELECT * FROM CustomersByContinent('South America') SELECT * FROM CustomersbyContinent('Unknown')

21 FUNCTION Samples (3) Multi Statement Table Valued CREATE FUNCTION varchar(15) ) table ( [CustomerID] [nchar] (5), [CompanyName] [nvarchar] (40), [ContactName] [nvarchar] (30), [ContactTitle] [nvarchar] (30), [Address] [nvarchar] (60), [City] [nvarchar] (15), [PostalCode] [nvarchar] (10), [Country] [nvarchar] (15), [Phone] [nvarchar] (24), [Fax] [nvarchar] (24) ) AS BEGIN

22 FUNCTION Samples (3) Multi Statement Table Valued INSERT SELECT [CustomerID], [CompanyName], [ContactName], [ContactTitle], [Address], [City], [PostalCode], [Country], [Phone], [Fax] FROM [Northwind].[dbo].[Customers] WHERE country

23 FUNCTION Samples (3) Multi Statement Table Valued INT = COUNT(*) = 0 INSERT ( [CustomerID], [CompanyName], [ContactName], [ContactTitle], [Address], [City], [PostalCode], [Country], [Phone], [Fax] ) VALUES ('','No Companies Found','','','','','','','','') RETURN END

24 FUNCTION Samples (3) Multi Statement Table Valued SELECT * FROM dbo.customersbycountry('usa') SELECT * FROM dbo.customersbycountry('canada') SELECT * FROM dbo.customersbycountry('adf')

25 Apakah TRIGGER itu? TRIGGER Sekumpulan perintah yang secara otomatis dijalankan apabila data didalam tabel berubah karena perintah SQL (insert, update, delete)

26 a. Melakukan update data otomatis ketika terjadi perubahan b. Mengimplementasikan sistem log. c. Validasi dan verifikasi data sebelum data tersebut tersimpan. Keuntungan Menggunakan TRIGGER

27 Timing Trigger FOR / AFTER, trigger dijalankan setelah DML Event pada tabel. INSTEAD OF, trigger dijalankan sebelum DML Event pada tabel. INSTEAD OF dapat dijalankan pada sebuah view. Event Trigger INSERT, trigger dijalankan pada saat melakukan penambahan data. UPDATE, trigger dijalankan pada saat melakukan update data. DELETE, trigger dijalankan pada saat data dihapus.

28 TRIGGER Samples (1) CREATE TABLE dbo.audittrail ( AuditTrailID Int IDENTITY (1, 1) NOT NULL, TableName VarChar (50) NOT NULL, ActionTaken Char (1) NOT NULL, ActionUser VarChar (50) NOT NULL, ActionDate DateTime NOT NULL ) ON [PRIMARY] Column Datatype NULL AuditTrailID Identity Not allowed TableName VarChar(50) Not allowed ActionTaken Char(1) Not allowed ActionUser VarChar(50) Not Allowed ActionDate DateTime Not Allowed

29 TRIGGER Samples (1) CREATE TRIGGER [AuditInsertUpdate] ON dbo.products FOR INSERT, UPDATE AS INSERT INTO AuditTrail (TableName, ActionTaken, ActionUser, ActionDate) VALUES ('Products', 'I', User_Name(), GetDate()) CREATE TRIGGER [AuditDelete] ON dbo.products FOR DELETE AS INSERT INTO AuditTrail (TableName, ActionTaken, ActionUser, ActionDate) VALUES ('Products', 'D', User_Name(), GetDate())

30 TRIGGER Samples (1) UPDATE dbo.products SET UnitPrice = 1 WHERE ProductID = 1 SELECT * FROM dbo.audittrail

31 TRIGGER Samples (2) CREATE TABLE [dbo].[triggertest] ([au_id] [int] NULL, [au_name] [varchar] (50)) CREATE TRIGGER tr_insertconcatname ON employees FOR INSERT AS INT VARCHAR(50) = (SELECT EmployeeID FROM Inserted) = (SELECT LastName + ', ' + FirstName FROM Inserted) INSERT TriggerTest VALUES (@EmpID,@ConcatName) INSERT employees (employeeid, lastname, firstname, title) VALUES (10,'Woody', 'Buck', Sales Manager )

32 TRIGGER Samples (2) CREATE TRIGGER tr_updateconcatname ON employees FOR UPDATE AS INT VARCHAR(50) = (SELECT EmployeeID FROM Inserted) = (SELECT Lastname + ', ' + Firstname FROM Inserted) UPDATE TriggerTest SET au_name WHERE au_id UPDATE employees SET firstname = 'Greg' WHERE EmployeeID = 10

33 TRIGGER Samples (2) CREATE TRIGGER tr_deleteconcatname ON employees FOR DELETE AS INT =(SELECT EmployeeID FROM Deleted) DELETE FROM TriggerTest WHERE au_id DELETE FROM employees WHERE EmployeeID = 10

34 Apakah DYNAMIC SQL Itu? DYNAMIC SQL Suatu teknik pemrograman SQL Code yang memungkinkan menuliskan perintah SQL secara dinamis sebelum dieksekusi

35 4 a. Isi perintah SQL ditentukan pada saat sebelum dieksekusi. b. Fleksibilitas karena perintah SQL dianggap sebagai STRING. c. Tidak perlu compile ulang jika terjadi perubahan perintah SQL. Keuntungan Menggunakan DINAMIC SQL

36 Static SQL Dinamic SQL STATIC SQL Isi perintah tidak dapat dirubah pada saat eksekusi (runtime). Perintah SQL dianggap sebagai bagian dari program. Fleksibilitas rendah karena perintah SQL dianggap sudah fix/tetap. Sebagian proses dilakukan pada saat kompilasi sehingga secara umum performansi lebih baik dibanding Dynamic SQL. DYNAMIC SQL Isi perintah belum dapat diketahui sebelum eksekusi (runtime) shg harus ditentukan pada saat runtime. Perintah SQL dianggap sebagai string biasa sebelum proses eksekusi. Fleksibilitas tinggi karena perintah SQL dapat diubah-ubah pada saat eksekusi. Semua proses dilakukan pada saat eksekusi sehingga secara umum performansi kurang dibanding Static SQL.

37 Bagaimana menjalankan? Dinamic SQL Membuat Query dengan Parameter Menggunakan EXEC Menggunakan sp_executesql

38 Dynamic SQL Samples (1) nvarchar(15) SELECT * FROM customers WHERE city=@city varchar(1000) varchar(75) nvarchar(15) = 'CustomerID, ContactName, City' = '''London''' = 'SELECT ' + ' FROM customers WHERE City = ' EXEC (@sqlcommand) nvarchar(1000) varchar(75) nvarchar(15) = 'CustomerID, ContactName, City' = '''London''' = 'SELECT ' + ' FROM customers WHERE City EXECUTE N'@city

39 Dynamic SQL Samples (2) CREATE PROCEDURE VarChar(100) AS VarChar(1000) = 'SELECT * FROM ' EXEC (@SQL) Dinamic SQL pada STORED PROCEDURE

40 Apakah CURSOR itu? CURSOR Object database yang dapat menampung banyak data untuk dimanipulasi baris per baris.

41 5 a. Menghasilkan data-data spesifik sesuai kebutuhan. b. Membantu penggunaan stored procedure yang berhubungan dengan manipulasi data. Keuntungan Menggunakan CURSOR

42 Daur Hidup Cursor» DECLARE, mendeklarasikan cursor sehingga terbentuk di memory Server Database.» OPEN, mengaktifkan cursor sehingga cursor dapat menampung data.» FETCH, mengambil data dari cursor untuk ditampung kedalam variabel.» WHILE, melakukan perulangan pada cursor jika operasi FETCH berhasil.» CLOSE, menonaktifkan cursor, tetapi bisa dibuka kembali.» DEALLOCATE, menghapus cursor, sehingga tidak bisa dibuka kembali.

43 DECLARE cursor_name [INSENSITIVE] [SCROLL] CURSOR FOR select_statement [FOR {READ ONLY UPDATE [OF column_name [,...n]]}] OPEN { { [GLOBAL] cursor_name } cursor_variable_name} CURSOR Syntax FETCH [[ NEXT PRIOR FIRST LAST ABSOLUTE RELATIVE ] FROM ] { { [GLOBAL] cursor_name ] CLOSE { {[GLOBAL] cursor_name } cursor_variable_name } DEALLOCATE { { [GLOBAL] cursor_name

44 CURSOR Samples nvarchar(40) int CURSOR = CURSOR FOR SELECT ProductName FROM Products FETCH NEXT = 0 BEGIN PRINT 'Product #' + CAST(@idx AS char(3)) SET FETCH NEXT END

45 Thank You & Good Luck THE END