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

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Stored Procedures, Function, Trigger,

Dynamic SQL, Cursor

Introduction

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Apa Itu

Smart Database ??

Database yang menyimpan “bisnis logic”

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

Database yang “konsisten”

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3-Tier

Architecture

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Object-Object

Smart Database

Stored

Procedures

Function

Trigger

Dynamic

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STORED PROCEDURES

Apakah STORED PROCEDURES itu?

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a. Eksekusi yang sudah dikompilasi.

b. Mengurangi trafik client/server.

c. Efisiensi penggunaan code dan

abtraksi pemrograman.

d. Meningkatkan control

keamanan pengguna.

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St

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CREATE PROC[EDURE]

procedure

[

schema

[ { @

parameter

.]

[

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

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EXEC

GetProducts

CREATE

PROCEDURE

[dbo].[GetProducts] AS

SELECT

ProductID, ProductName

FROM

Products

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STORED PROCEDURES

Samples (2)

CREATE

PROCEDURE

OrderSummary @MaxQuantity 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

SELECT

@MaxQuantity =

MAX(Quantity

)

FROM

[Order Details]

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STORED PROCEDURES

Samples (2)

DECLARE

@OrderSum INT

DECLARE

@LargestOrder INT

EXEC

@OrderSum = OrderSummary

@MaxQuantity = @LargestOrder OUTPUT

PRINT

'The size of the largest single order was: '

+ CONVERT(CHAR(6), @LargestOrder)

PRINT

'The sum of the quantities ordered was: '

+ CONVERT(CHAR(6), @OrderSum)

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EXEC

CustomerOrder @CustID=

'WILMK'

CREATE PROCEDURE

CustomerOrder

@CustID nvarchar(5)

AS

SELECT

orderID,CustomerId,OrderDate

FROM

Orders

WHERE

CustomerID=@CustID

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FUNCTION

Apakah FUNCTION itu?

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Keuntungan Menggunakan FUNCTION

a. Penggunaan kembali code,

sehingga mengurangi waktu

pembuatan.

b. Menyembunyikan detail SQL.

c. Tersentralisasi, sehingga

memudahkan jika bisnis logic

mengalami perubahan.

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Perbedaan STORED PROCEDURES dan FUNCTION

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

Stored Procedure dapat

mengembalikan banyak nilai menggunakan parameter

OUT, atau tidak

mengembalikan nilai sama sekali.

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Fu

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CREATE FUNCTION

[schema.] function

( [@parameter [ AS ][type_schema.]

parameter_data_type [= default ]

[ ,...n ]

])

RETURNS

return_clause...

[;]

ALTER FUNCTION

DROP

FUNCTION

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Ada 3 tipe User-Defined Functions :

Tipe Function

1. Scalar

2. Inline

Table-Valued

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FUNCTION

Samples (1) - Scalar

CREATE FUNCTION WhichContinent (@Country nvarchar(15))

RETURNS varchar(30)

AS

BEGIN

declare @Return varchar(30)

select @Return = case @Country

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

return @Return

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FUNCTION

Samples (1) - Scalar

PRINT dbo.WhichContinent('USA')

SELECT dbo.WhichContinent(Customers.Country), customers.* FROM

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FUNCTION

Samples (2) – Inline Table Valued

CREATE FUNCTION CustomersByContinent (@Continent varchar(30)) RETURNS TABLE AS RETURN SELECT dbo.WhichContinent(Customers.Country) as continent, customers.* FROM customers WHERE dbo.WhichContinent(Customers.Country) = @Continent

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FUNCTION

Samples (2) – Inline Table Valued

SELECT * FROM CustomersbyContinent('North America')

SELECT * FROM CustomersByContinent('South America')

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FUNCTION

Samples (3) – Multi Statement Table Valued

CREATE FUNCTION dbo.customersbycountry( @Country varchar(15) )

RETURNS @CustomersbyCountryTab 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

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FUNCTION

Samples (3) – Multi Statement Table Valued

INSERT INTO @CustomersByCountryTab

SELECT [CustomerID], [CompanyName], [ContactName], [ContactTitle], [Address], [City], [PostalCode], [Country], [Phone], [Fax] FROM [Northwind].[dbo].[Customers]

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FUNCTION

Samples (3) – Multi Statement Table Valued

DECLARE @cnt INT

SELECT @cnt = COUNT(*) FROM @customersbyCountryTab

IF @cnt = 0

INSERT INTO @CustomersByCountryTab ( [CustomerID], [CompanyName], [ContactName], [ContactTitle], [Address], [City], [PostalCode], [Country], [Phone], [Fax] )

VALUES ('','No Companies Found','','','','','','','','')

RETURN END

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FUNCTION

Samples (3) – Multi Statement Table Valued

SELECT * FROM dbo.customersbycountry('USA')

SELECT * FROM dbo.customersbycountry('CANADA')

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TRIGGER

Apakah TRIGGER itu?

“Sekumpulan perintah yang secara otomatis dijalankan apabila data didalam tabel berubah

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Keuntungan Menggunakan TRIGGER

a. Melakukan update data

otomatis ketika terjadi

perubahan

b. Mengimplementasikan

sistem log.

c. Validasi dan verifikasi data

sebelum data tersebut

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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.

Timing Trigger

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.

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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

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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)

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TRIGGER

Samples (1)

UPDATE dbo.Products SET UnitPrice = 1

WHERE ProductID = 1

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TRIGGER

Samples (2)

CREATE TABLE [dbo].[TriggerTest] ([au_id] [int] NULL,

[au_name] [varchar] (50))

CREATE TRIGGER tr_InsertConcatName ON employees

FOR INSERT AS

DECLARE @EmpID INT

DECLARE @ConcatName VARCHAR(50)

SELECT @EmpID = (SELECT EmployeeID FROM Inserted)

SELECT @ConcatName = (SELECT LastName + ', ' + FirstName FROM Inserted)

INSERT TriggerTest VALUES (@EmpID,@ConcatName)

INSERT employees (employeeid, lastname, firstname, title)

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TRIGGER

Samples (2)

CREATE TRIGGER tr_UpdateConcatName ON employees

FOR UPDATE AS

DECLARE @NewConcatName VARCHAR(50)

SELECT @EmpID = (SELECT EmployeeID FROM Inserted)

SELECT @NewConcatName = (SELECT Lastname + ', ' + Firstname FROM Inserted)

UPDATE TriggerTest SET au_name = @NewConcatName WHERE au_id = @EmpID

UPDATE employees SET firstname = 'Greg' WHERE EmployeeID = 10

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TRIGGER

Samples (2)

CREATE TRIGGER tr_DeleteConcatName

ON employees FOR DELETE AS

SELECT @EmpID =(SELECT EmployeeID FROM Deleted)

DELETE FROM TriggerTest WHERE au_id = @EmpID

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DYNAMIC SQL

Apakah DYNAMIC SQL Itu?

“Suatu teknik pemrograman SQL Code yang memungkinkan menuliskan perintah SQL secara

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4

Keuntungan Menggunakan DINAMIC SQL

a. Isi perintah SQL ditentukan

pada saat sebelum dieksekusi.

b. Fleksibilitas karena perintah SQL

dianggap sebagai

S

T

R

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N

G

.

c. Tidak perlu compile ulang jika

terjadi perubahan perintah SQL.

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Static SQL

Dinamic SQL

STATIC SQL

DYNAMIC SQL

Isi perintah tidak dapat dirubah pada saat eksekusi (runtime).

Isi perintah belum dapat diketahui sebelum eksekusi (runtime) shg harus ditentukan pada saat runtime.

Perintah SQL dianggap sebagai bagian dari

program. Perintah SQL dianggap sebagai string biasa sebelum proses eksekusi. Fleksibilitas rendah karena perintah SQL

dianggap sudah fix/tetap. Fleksibilitas tinggi karena perintah SQL dapat diubah-ubah pada saat eksekusi. Sebagian proses dilakukan pada saat

kompilasi sehingga secara umum performansi lebih baik dibanding Dynamic SQL.

Semua proses dilakukan pada saat

eksekusi sehingga secara umum

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?

Bagaimana menjalankan

Dinamic SQL…

Membuat Query dengan

Parameter

Menggunakan

EXEC

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Dynamic SQL

Samples (1)

DECLARE @City nvarchar(15)

SET @city='Paris'

SELECT * FROM customers WHERE city=@city

DECLARE @sqlCommand varchar(1000)

DECLARE @columnList varchar(75)

DECLARE @city nvarchar(15)

SET @columnList = 'CustomerID, ContactName, City'

SET @city = '''London'''

SET @sqlCommand = 'SELECT ' + @columnList + ' FROM customers WHERE City = ' + @city

EXEC (@sqlCommand)

DECLARE @sqlCommand nvarchar(1000)

DECLARE @columnList varchar(75)

DECLARE @city nvarchar(15)

SET @columnList = 'CustomerID, ContactName, City'

SET @city = '''London'''

SET @sqlCommand = 'SELECT ' + @columnList + ' FROM customers WHERE City = @city'

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Dynamic SQL

Samples (2)

Dinamic SQL pada STORED PROCEDURE

CREATE PROCEDURE GenericTableSelect @TableName VarChar(100)

AS

DECLARE @SQL VarChar(1000)

SET @SQL = 'SELECT * FROM '

SET @SQL = @SQL + @TableName

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CURSOR

Apakah CURSOR itu?

“Object database yang dapat menampung banyak data untuk dimanipulasi baris per baris.”

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5

Keuntungan Menggunakan CURSOR

a. Menghasilkan data-data

spesifik sesuai kebutuhan.

b. Membantu penggunaan

stored procedure yang

berhubungan dengan

manipulasi data.

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» 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.

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DECLARE cursor_name [INSENSITIVE] [SCROLL] CURSOR FOR select_statement

[FOR {READ ONLY | UPDATE [OF column_name [,...n]]}]

OPEN { { [GLOBAL] cursor_name } | cursor_variable_name}

FETCH

[[ NEXT | PRIOR | FIRST | LAST | ABSOLUTE {n | @nvar} | RELATIVE {n | @nvar} ] FROM ] { { [GLOBAL] cursor_name } | @cursor_variable_name} [INTO @variable_name[,...n] ]

CLOSE { {[GLOBAL] cursor_name } | cursor_variable_name }

DEALLOCATE { { [GLOBAL] cursor_name } |

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CURSOR

Samples

DECLARE @ProductName nvarchar(40)

DECLARE @idx int

SET @idx=1

DECLARE @getProductName CURSOR

SET @getProductName = CURSORFOR SELECT ProductName FROM Products

OPEN @getProductName

FETCH NEXT FROM @getProductName INTO @ProductName

WHILE @@FETCH_STATUS = 0

BEGIN

PRINT 'Product #' + CAST(@idx AS char(3)) + @ProductName

SET @idx= @idx+1

FETCH NEXT FROM @getProductName INTO @ProductName

END

CLOSE @getProductName

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