ADO.NET Objects – Data Providers

Dr. Ron Eaglin

Requirements

• Visual Studio 2005

• Microsoft SQL Server 2000 or 2005– Adventure Works Database Installed– Database available on local machine

Agenda

• Working with the Database Connection Object– ConnectionString property– Visual Creation of Connection– Code Creation of Connection

– Runtime Connections

Database ConnectionsCreate a new project

Windows application

Name project:AdventureWorksDemo1

Using Toolbox

• Right click on the data icon in the toolbox

• Select “Choose items …”

• This will bring up a dialog allowing you to select all items displayed from the list of available tools.

Data “items”Select SQLConnection fromList of available tools

The SQLConection objectWill now be in your Toolbox

Adding SQLConnection to FormDrag and dropSQLConnectionObject ontoForm.

SQL Connection ObjectSelect the SQLConnection object in the form and look at the Properties dialog box. Select the ConnectionString propertyAnd select <New Connection>

Add Connection

Select your server

Select AdventureWorks database

Test the connection

Add Connection

• ConnectionString property will fill with the text that allows the connection.

• ConnectionString has form

Keyword=value;keyword=value;keyword=value

Example:

Data Source=WHITEWATER;Initial Catalog=AdventureWorks;Integrated Security=True

Adding Connection String with Code Add button to form and

Change text of button

Double click button for Code window

Button Code windowEnter code here

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

' Create a new connection object of type SQLConnection Dim RuntimeConnection As New Data.SqlClient.SqlConnection ' Set the connection string RuntimeConnection.ConnectionString = "Data Source=WHITEWATER;Initial Catalog=AdventureWorks;Integrated Security=True"

Try RuntimeConnection.Open() MsgBox("Connection with connection string " + RuntimeConnection.ConnectionString + " opened successfully", MsgBoxStyle.Information) Catch ex As Exception MsgBox("Connection with connection string " + RuntimeConnection.ConnectionString + " failed to open", MsgBoxStyle.Information) End Try

RuntimeConnection.Close()

End Sub

Test Application

Add code to test SQLConnection1 Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Try SqlConnection1.Open() MsgBox("Connection with connection string " + SqlConnection1.ConnectionString + " opened successfully", MsgBoxStyle.Information) Catch ex As Exception MsgBox("Connection with connection string " + SqlConnection1.ConnectionString + " failed to open", MsgBoxStyle.Information) End Try

SqlConnection1.Close() End Sub

Test SQLConnection1

SQLConnection Properties

• ConnectionString

• ConnectionTimeout

• Database

• DataSource

• ServerVersion

• State

Other types of Connections

• SQLConnection is specific to SQl Server only

• ODBCConnection – any ODBC database

• OLEDBConnection – Any OLE DB datasource

• OracleConnection

Agenda

• Creating and using a DataCommand object

• Issuing Database commands using the DataCommand object.

DataCommand object

• DataCommand is a simple ADO.NET wrapper for a SQL Statement.

• Using DataCommand from design and from run-time.

Design Window SQLCommand

• If SQLCommand is not in your toolbox, right click and add it to your toolbox using the Choose Items…

• Drag and drop the SQLCommand on to your form.

SQLCommand addedSQLCommand object inform

SQLCommand

• Properties of the SQLCommand– Connection– CommandType

• Text• StoredProcedure• TableDirect

– Parameters

SQLCommand1 Properties

• Set Connection = SQLConnection1

• Set CommandType = Text

• Click on … dialog on CommandText Property

Clicking on boxWill bring up queryBuilder.

Once the query is built – it is possible to use the previewData link in the properties window.

Runtime SQLCommand

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click Dim rtSQLCommand As New Data.SqlClient.SqlCommand

rtSQLCommand.Connection = SqlConnection1rtSQLCommand.CommandType = CommandType.TextrtSQLCommand.CommandText = "SELECT Person.Address.* FROM Person.Address"

End Sub

SQLCommand

• Note that running the code to create the runtime SQLCommand – does not actually do anything.

• We must execute the Command and also have a place for the results.

DataReader Object

• A DataReader is a lightweight object meant to hold the results of a SQLCommand

• DataReaders can be treated as a cursor to go through the DB values.

DataReader

SqlConnection1.Open() Dim rtDataReader1 As Data.SqlClient.SqlDataReader rtDataReader1 = rtSQLCommand.ExecuteReader

If rtDataReader1.HasRows = True Then MsgBox("The reader has found rows", MsgBoxStyle.Information) End IfSqlConnection1.Close()

Add this code to the previous code

Binding the Data ReaderAdd ListboxTo Form

Add code

While rtDataReader1.Read ListBox1.Items.Add(rtDataReader1.GetValue(1)) End While

Add code before closing the connection, after executing the reader.

Results of Code

Data from first field of DB Query is added to the list.

DataReader Methods

• Open code window

• Put cursor on the code

Dim rtDataReader1 As Data.SqlClient.SqlDataReader

Hit F1

Put cursor here

Help on DataReaderCode examples of using Data Reader

More code

Review

• Working with Database Connection

• Creating code to use database

• Using Command Objects

• Using the Data Reader Object

• Displaying Database Results

• Getting More Information on Objects