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Visual Basic .NET Programming
What is What is What is What is ADOADOADOADO....NETNETNETNET????
Data Access Object
Remote Data Object
Active Data Object
ADO.NET * Property of STIPage 1 of 19
� ADO .Net
� group of libraries
� allow applications to read and update
information in databases and other sources
� includes two .NET data providers:
• SQL Server .NET Data provider
• OLE DB .NET Data Provider
ActiveX Data Object for .Net Framework
Visual Basic .NET Programming
ADOADOADOADO....NETNETNETNETArchitectureArchitectureArchitectureArchitecture
ADO.NET * Property of STIPage 2 of 19
Visual Basic .NET Programming
....NETNETNETNET Data Data Data Data ProvidersProvidersProvidersProviders
� System.Data.SQLClient namespace
� used for SQL Server 7.0 and later
databases
� System.Data.OleDb namespace
� used for all other databases
ADO.NET * Property of STIPage 3 of 19
� Components:
� Connection object
� Command object
� DataReader object
� DataAdapter object
Visual Basic .NET Programming
Connection Connection Connection Connection ObjectObjectObjectObject
� creates the connection to the database
� connection classes:
� SqlConnection object
� OleDbConnection object
� Steps in connecting to a database:
ADO.NET * Property of STIPage 4 of 19
� Steps in connecting to a database:
� Set the connection type
� Specify the data source
� Connect to the data source
Visual Basic .NET Programming
SqlConnection SqlConnection SqlConnection SqlConnection ObjectObjectObjectObject
� has a property that contains all the information in establishing a connection
� ConnectionString property
� consists of name-value pairs
� Some common keywords used are:
Connection Timeout / Connect Timeout
ADO.NET * Property of STIPage 5 of 19
� Connection Timeout / Connect Timeout
� Initial Catalog
� User ID
� Password / Pwd
� Data Source / Server/ Address / Addr /Network Address
� Integrated Security / Trusted_Connection
Visual Basic .NET Programming
Example: SQL ClientExample: SQL ClientExample: SQL ClientExample: SQL Client....NETNETNETNET Data ProviderData ProviderData ProviderData Provider
Imports System
Imports System.Data.SqlClient
Module SQLClientDemo
Public Sub Main()
Dim strConnection As String =
“Integrated Security=True;Data
Source=Localhost;Initial
ADO.NET * Property of STIPage 6 of 19
Source=Localhost;Initial
Catalog=Pubs;”
Dim conServer As SqlConnection =
New SqlConnection
conServer.ConnectionString =
strConnection
conserver.Open()
End Sub
End Module
Visual Basic .NET Programming
OleDbConnectionOleDbConnectionOleDbConnectionOleDbConnectionObjectObjectObjectObject
� uses a ConnectionString property similar
to SQLConnection but with some
additional keywords such as Provider,
URL, Remote Provider and Remote Server
Imports System
Imports System.Data.OleDb
Module OleDbDemo
ADO.NET * Property of STIPage 7 of 19
Public Sub Main()
Dim strConnection As String =
“Provider=Microsoft.Jet.OLEDB.4.
0;Data Source=C:\NWind.MDB”
Dim conServer As OleDbConnection
= New OleDbConnection
conServer.ConnectionString =
strConnection
conserver.Open()
End Sub
End Module
Visual Basic .NET Programming
Creating Creating Creating Creating CommandsCommandsCommandsCommands
� ADO.NET Command object is used to
execute commands
� SqlCommand
� used for SQL Server database
� OleDBCommand
� used for all other types of databases
� Ways to create a Command:
ADO.NET * Property of STIPage 8 of 19
� Ways to create a Command:
� use the Command constructor and pass the
Connection object as an argument
� use the CreateCommand method of the
Connection object
Visual Basic .NET Programming
Creating Creating Creating Creating CommandsCommandsCommandsCommands
Imports System
Imports System.Data.SqlClient
Module SQLClientDemo
Public Sub Main()
Dim strConnection As String =
“Integrated Security=True;Data
Source=Localhost;Initial
Catalog=Pubs;”
Dim conServer As SqlConnection = New
ADO.NET * Property of STIPage 9 of 19
Dim conServer As SqlConnection = New
SqlConnection
conServer.ConnectionString =
strConnection
conserver.Open()
‘the code that will create a Command
Dim commSQL As SqlCommand = New
SqlCommand
commSql.Connection = conserver
commSql.Commandtext = “Select
count(*) from Employees”
End Sub
End Module
Visual Basic .NET Programming
Executing Executing Executing Executing CommandsCommandsCommandsCommands
� Methods used to execute a Command:
� ExecuteReader
• used when the query will return a stream of
data
� ExecuteScalar
• used when the query return a single value
ADO.NET * Property of STIPage 10 of 19
• used when the query return a single value
� ExecuteNonQuery
• used when the query will not return a
result
� ExecuteXMLReader
• used when the query includes a valid FOR
XML clause and it is valid only in
SqlCommand object
Visual Basic .NET Programming
Imports System
Imports System.Data.SqlClient
Module SQLClientDemo
Public Sub Main()
Dim strConnection As String =
“Integrated Security=True;Data
Source=Localhost;Initial Catalog=Pubs;”
Dim conServer As SqlConnection = New
SqlConnection
Example of Example of Example of Example of Executing CommandsExecuting CommandsExecuting CommandsExecuting Commands
ADO.NET * Property of STIPage 11 of 19
SqlConnection
conServer.ConnectionString =
strConnection
conserver.Open()
Dim commSQL As SqlCommand = New
SqlCommand
commSql.Connection = conserver
commSql.Commandtext = “Select count(*)
from Employees”
‘the code that will query a database and
‘retrieve data
MessageBox.Show(commSql.ExecuteScalar()
.ToString)
End Sub
End Module
Visual Basic .NET Programming
DataReader DataReader DataReader DataReader ObjectObjectObjectObject
� DataReader object
� used to read a single row of data at a time
• SqlDataReader
• OleDbDataReader
� Create an instance of the DataReader
object:
� ExecuteReader method
ADO.NET * Property of STIPage 12 of 19
� ExecuteReader method
� Read method
� Get Method
� Example of Read method
Dim datRead As SqlDataReader = New
SqlDataReader
datRead = commSql.ExecuteReader()
Do Until datRead.Read = False
MessageBox.Show(datRead(1).ToString
& “ “ & datRead(0).ToString)
Loop
datRead.Close()
Visual Basic .NET Programming
DataReader DataReader DataReader DataReader ObjectObjectObjectObject
� Example of Get Method
Dim datRead As SqlDataReader = New
SqlDataReader
datRead = commSql.ExecuteReader()
Do Until datRead.Read = False
ADO.NET * Property of STIPage 13 of 19
MessageBox.Show(datRead.GetString
(1) & “ “ &
datRead.GetString(0))
Loop
Visual Basic .NET Programming
DataAdapter DataAdapter DataAdapter DataAdapter ObjectObjectObjectObject
� used to link between data source and
cached tables
� Ways to create a DataAdapter object:
� Using an existing Connection object
� Using a closed connection
ADO.NET * Property of STIPage 14 of 19
Visual Basic .NET Programming
DataAdapter DataAdapter DataAdapter DataAdapter ObjectObjectObjectObject
� Example of using an existing Connection objectImports System
Imports System.Data.SqlClient
Module SQLClientDemo
Public Sub Main()
Dim strConnection As String = “Integrated Security=True;Data Source=Localhost;Initial Catalog=Books;”
Dim conServer As SqlConnection = New SqlConnection
ADO.NET * Property of STIPage 15 of 19
SqlConnection
conServer.ConnectionString = strConnection
conserver.Open()
Dim commSQL As SqlCommand = New SqlCommand
commSql.Connection = conserver
commSql.Commandtext = “Select count(*) from Catalogue”
‘the code that will create a DataAdapter
Dim adaptSQL As SqlDataAdapter = New SqlDataAdapter
adaptSQL.SelectCommand = commSQL
End Sub
End Module
Visual Basic .NET Programming
DataAdapter DataAdapter DataAdapter DataAdapter ObjectObjectObjectObject
� Example of using a closed connection
Private conServer As
SqlClient.SqlConnection
Public Sub Form1_Load(ByVal sender As
System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
conserver = New
SqlClient.SqlConnection()
Dim strConnection As String =
ADO.NET * Property of STIPage 16 of 19
Dim strConnection As String =
“Integrated Security=True;Data
Source=Localhost;Initial
Catalog=Books;”
conServer.ConnectionString =
strConnection
conserver.Open()
End Sub
Private Sub Button1_Click ByVal sender As
System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
‘the code that will create a DataAdapter
Dim adaptSQL As
SqlClient.SqlDataAdapter(“Select
count(*) from Catalogue”, conserver)
End Sub
Visual Basic .NET Programming
Populating the Populating the Populating the Populating the DataTableDataTableDataTableDataTable
� DataTable class
� represents one table of in-memory data
� a central object in the ADO.NET library
� Fill method
� used by passing a DataSet and optionally
the required DataTable as parameters
ADO.NET * Property of STIPage 17 of 19
the required DataTable as parameters
� used to fill and update multiple DataSets
Visual Basic .NET Programming
Populating the Populating the Populating the Populating the DataTableDataTableDataTableDataTable
� Example of Fill method
Private conServer As
SqlClient.SqlConnection
Public Sub Form1_Load(ByVal sender
As System.Object, ByVal e As
System.EventArgs) Handles
MyBase.Load
ADO.NET * Property of STIPage 18 of 19
MyBase.Load
conserver = New
SqlClient.SqlConnection()
Dim strConnection As String =
“Integrated Security=True;Data
Source=Localhost;Initial
Catalog=Books;”
conServer.ConnectionString =
strConnection
conserver.Open()
End Sub
Visual Basic .NET Programming
Populating the Populating the Populating the Populating the DataTableDataTableDataTableDataTable
� Example of Fill method (con’t)
Private Sub Button1_Click ByVal
sender As System.Object, ByVal
e As System.EventArgs) Handles
Button1.Click
Dim adaptSQL As
SqlClient.SqlDataAdapter(“Select
ADO.NET * Property of STIPage 19 of 19
SqlClient.SqlDataAdapter(“Select
count(*) from Catalogue”,
conserver)
‘the code that will fill the
DataSet
Dim datBooks As New DataSet()
adaptSQL.Fill(datBooks,
“MyTable”)
‘manipulate data locally using
DataSet
adaptSQL.Update(datBooks,
“MyTable”)
End Sub