📄 update-with-command.aspx
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<%@Page Language="VB"%>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.OleDb" %>
<%@ Register TagPrefix="wrox" TagName="connect" Src="..\global\connect-strings.ascx" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html><head>
<title>Updating Data with a Command Object</title>
<style type="text/css">
body, td {font-family:Tahoma,Arial,sans-serif; font-size:10pt}
input {font-family:Tahoma,Arial,sans-serif; font-size:9pt}
.heading {font-family:Tahoma,Arial,sans-serif; font-size:14pt; font-weight:bold}
.subhead {font-family:Tahoma,Arial,sans-serif; font-size:12pt; font-weight:bold; padding-bottom:5px}
.cite {font-family:Tahoma,Arial,sans-serif; font-size:8pt}
</style></head>
<body bgcolor="#ffffff">
<span class="heading">Updating Data with a Command Object</span><hr />
<!--------------------------------------------------------------------------->
<%'-- insert connection string script --%>
<wrox:connect id="ctlConnectStrings" runat="server"/>
<div>Connection string: <b><span id="outConnect" runat="server"></span></b></div>
<div>SQL statement: <b><span id="outSQL" runat="server"></span></b></div>
<div id="outError" runat="server"> </div>
<div id="outResult" runat="server"></div>
<script language="vb" runat="server">
Sub Page_Load()
'get connection string from ..\global\connect-strings.ascx user control
Dim strConnect = ctlConnectStrings.OLEDBConnectionString
outConnect.InnerText = strConnect 'and display it
'specify the SQL statement to update the data
Dim datNow As DateTime = Now()
Dim strNow As String = datNow.ToString("dd-M-yy \a\t hh:mm:ss")
Dim strSQL As String
strSQL = "UPDATE BookList SET Title = 'New Book Written on " _
& strNow & "' WHERE ISBN='1861003005'"
outSQL.InnerText = strSQL 'and display it
'create a new Connection object using the connection string
Dim objConnect As New OleDbConnection(strConnect)
'create a new Command using the connection object and select statement
Dim objCommand As New OleDbCommand(strSQL, objConnect)
'declare an Integer variable to hold the number of records affected
Dim intRowsAffected As Integer
Try
'open the connection to the database
objConnect.Open()
'execute the SQL statement against the command
'the ExecuteNonQuery method returns the number of records affected
intRowsAffected = objCommand.ExecuteNonQuery()
Catch objError As Exception
'display error details
outError.InnerHtml = "<b>* Error while updating original data</b>.<br />" _
& objError.Message & "<br />" & objError.Source
Exit Sub ' and stop execution
End Try
'declare a string to display the results
Dim strResult As String
'show the number of records affected
strResult = "Executed SQL statement, <b>" & intRowsAffected.ToString() _
& "</b> record(s) affected<br />Reading back from the database...<br />"
'read the data back again - specify a SQL statement to
'extract just this record for the existing Command object
objCommand.CommandText = "SELECT * FROM BookList WHERE ISBN='1861003005'"
Try
'declare a variable to hold a DataReader object
Dim objDataReader As OleDbDataReader
'execute the SQL statement against the command to fill the DataReader
objDataReader = objCommand.ExecuteReader()
'iterate through the records in the DataReader getting field values
'the Read method returns False when there are no more records
Do While objDataReader.Read()
strResult += "ISBN=""<b>" & objDataReader("ISBN") & "</b>"" Title=""<b>" _
& objDataReader("Title") & """</b>"
Loop
'close the DataReader and Connection
objDataReader.Close()
objConnect.Close()
Catch objError As Exception
'display error details
outError.InnerHtml = "<b>* Error while accessing updated data</b>.<br />" _
& objError.Message & "<br />" & objError.Source
Exit Sub ' and stop execution
End Try
'display the result
outResult.InnerHtml = strResult
End Sub
</script>
<!--------------------------------------------------------------------------->
<hr /><span class="cite">[<a href="..\global\viewsource.aspx">view source</a>]
©2001 <a class="cite" href="http://www.wrox.com/">Wrox Press</a> -
<a class="cite" href="http://www.wrox.com/Books/Book_Details.asp?isbn=1861004885">Professional ASP.NET</a> (ISBN: 1-861004-88-5)</span>
</body>
</html>
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