Topik 5.3 WorkwithADO.net

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F5227VISUAL BASIC .NET PROGRAMMING

Topic 5.3 :

Work with Data using ADO.NET


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Course Learning Outcome (CLO) Upon completion of this course, students should be able to :

1. Create a simple VB.NETbased application based on the

Windows Application template.

2. Describe on essential terminology including memory,data types and graphical user interface.

3. Apply object oriented programming techniques to

create classes, add methods and add properties.

4. create a simple VB.NET based Web forms applicationthat uses an XML Web Service and manipulate data in

database by using Microsoft ADO.NET.


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Course Learning Outcome:

Topic 5.0

1. create a simple VB.NET based Web forms application

that uses an XML Web Service and manipulate data in

database by using Microsoft ADO.NET


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Topic 5.0

Topic 5.1 : Understand with Web Forms

Topic 5.2 Create a web application using

VB.NET

Topic 5.3 : Work with Data using ADO.NET


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Introduction

ADO.NET(ActiveX Data Objects .NET) is the

primary data access API (Application

Programming Interface) for the .NET

Framework.

ADO.NET is a data access technology from

Microsoft .Net Framework , which provides

communication between relational and non-relational systems through a common set of

components
http://vb.net-informations.com/ado.net/ado.net-architecture.htmhttp://vb.net-informations.com/framework/what_is_net_framework.htmhttp://vb.net-informations.com/framework/what_is_net_framework.htmhttp://vb.net-informations.com/ado.net/ado.net-architecture.htm


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ADO.NET

ADO.NET provides the classes that you use as

you develop database applications with Visual

Basic .NET as well as other .


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ADO.NET consist of a set of Objects that

expose data access services to the .NET

environment. ADO.NET is built for

disconnected architecture , so it enables truly

disconnected Data Access and Data

Manipulation through its Dataset Object,

which is completely independent from theData Source.


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ADO.NET Architecture


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How ADO.NET works?


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ADO.NET uses two types of objects to access

the data in a database:

data providerobjects, which include data

adapters, commands, and connections.

datasets, which can contain one or more data

tables


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Data Providers

The .Net Framework includes mainly three

Data Providers for ADO.NET and they are:

Microsoft SQL Server Data Provider

OLEDB Data Provider

ODBC Data Provider.

SQL Server uses the SqlConnection object ,

OLEDB uses the OleDbConnection Object and

ODBC uses OdbcConnection Object

respectively.


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Data Providers

The ADO.NET classes that are responsible for

working directly with a database are provided

by the .NET data providers.

These data providers include the classes you

use to create data adapters, commands, and

connections.


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Data Providers

The four Objects from the.Net Framework provide the

functionality of Data

Providers in the ADO.NET.The Connection Object

provides physical

connection to the Data

Source.

The Command Object

uses to perform SQL

statement or stored

procedure to be

executed at the Data

Source

The DataReader Object is

a stream-based , forward-

only, read-only retrieval

of query results from the

Data Source, which do

not update the data.

DataAdapter

Object , which

populate a

Dataset Object

with results from

a Data Source .


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Data Adapter

To retrieve data from a database and store it

in a data table, a data adapterobject issues a

Select statement thats stored in a command

object.

Next, the command object uses a connection

object to connect to the database and retrieve

the data.

Then, the data is passed back to the data

adapter, which stores the data in the dataset.


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Command Object

To update the data in a database based on the

data in a data table, the data adapter object

issues an Insert, Update, or Delete statement

thats stored in a command object.

Then, the command object uses a connection

to connect to the database and update the

data.


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Data Provider

The data provider remains connected to the

database only long enough to retrieve or

update the specified data.

Then, it disconnects from the database and

the application works with the data via the

dataset object.

This is referred to as a disconnected data

architecture.


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Disconnected data

One of the advantages of using a disconnected

data architecture is improved system

performance due to the use of fewer system

resources for maintaining connections.

Another advantage is that it makes ADO.NET

compatible with ASP.NET web applications,

which are inherently disconnected.


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Dataset

A dataset stores data from the database so

that it can be accessed by the application.

The .NET data provider objects retrieve data

from and update data in the database.


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DataSet

DataSet provides a disconnected

representation of result sets from the Data

Source, and it is completely independent from

the Data Source.

DataSet provides much greater flexibility

when dealing with related Result Sets.


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DataSet

DataSet consists of a collection ofDataTable

objects that you can relate to each other with

DataRelation objects.

The DataTable contains a collection of

DataRow and DataCoulumn Object which

contains Data.

The DataAdapter Object provides a bridge

between the DataSet and the Data Source.


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DataSetThe DataTable contains a

collection of DataRow andDataColumn Object which

contains Data.


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Scenario

The data in a dataset is independent of the

database that the data was retrieved from.

In fact, the connection to the database is

typically closed after the data is retrieved from

the database.

Then, the connection is opened again when

its needed.


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Because of that, the application must work

with the copy of the data thats stored in the

dataset.

The architecture thats used to implement this

type of data processing is referred to as a

disconnected data architecture.


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ADO.NET Connection String

Connection String is a normal String

representation which contains Database

connection information to establish the

connection between Datbase and theApplication.

The Connection String includes parameters

such as the name of the driver, Server nameand Database name , as well as security

information such as user name and password.


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ADO.NET Connection String

Data providers use a connection string

containing a collection of parameters to

establish the connection with the database.

The .NET Framework provides mainly three

data providers: Microsoft SQL Server, OLEDB

and ODBC.


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All of the ADO.NET objects are implemented

by classes in the System.Data namespace of

the .NET Framework.


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Microsoft SQL Server Connection

String

Syntax:

connectionString ="Data Source = ServerName;

Initial Catalog = Databasename; User ID =

UserName; Password=Password"


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SQL Server Connection String

The SqlConnection Object is Handling the part

of physical communication between the

application and the SQL Server Database.

An instance of the SqlConnection class in .NET

Framework is supported the Data Provider for

SQL Server Database.


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SQL ConnectionImports System.Data.SqlClient

Public Class Form1Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles Button1.Click

Dim connectionString As String

Dim cnn As SqlConnection

connectionString = "Data Source=ServerName;Initial

Catalog=DatabaseName;User ID=UserName;Password=Password"

cnn = New SqlConnection(connetionString)

Try

cnn.Open()

MsgBox("Connection Open ! ")

cnn.Close()

Catch ex As Exception

MsgBox("Can not open connection ! ")

End Try

End Sub

End Class


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OLEDB Data Provider Connection

String

Syntax:

connectionString = "Provider =

Microsoft.Jet.OLEDB.4.0; Data Source =

yourdatabasename.mdb;"


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OLEDB ConnectionImports System.Data.OleDb

Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles Button1.Click

Dim connetionString As String

Dim cnn As OleDbConnection connetionString =

"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=yourdatabasename.mdb;"

cnn = New OleDbConnection(connetionString)

Try

cnn.Open()


cnn.Close()

Catch ex As Exception


End Try

End Sub

End Class


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ODBC Connection String

Syntax:

connectionString = "Driver = {Microsoft Access

Driver (*.mdb)}; DBQ =

yourdatabasename.mdb;"


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ODBC ConnectionImports System.Data.Odbc

Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVale As System.EventArgs) Handles Button1.Click

Dim connetionString As String

Dim cnn As OdbcConnection

connetionString = "Driver={Microsoft Access Driver

(*.mdb)};DBQ=yourdatabasename.mdb;"

cnn = New OdbcConnection(connetionString)

Try

cnn.Open()


cnn.Close()Catch ex As Exception


End Try

End Sub

End Class


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Two ways to create ADO.NET

objects

First, you can use the components in the Data

tab of the Toolbox to create ADO.NET objects

by dragging and dropping them onto a form.

The second technique for creating ADO.NET

objects is to write the code


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Creating ADO.NET


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.NET Providers


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The SqlConnection class

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Topik 5.3 WorkwithADO.net

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