----------------------------
Caching asp.net applications improve the performance.
Dim strprod As String
Dim strSelect As String
Dim con As OleDbConnection
Dim cmd As OleDbCommand
Dim dr As OleDbDataReader
strprod= Request.Param("PID")
if strprod = Nothing then
strprod=1
End if
con = New OleDbConnection("Provider=Microsoft.jet.OLEDB.4.0;
Data Source=c:\Nwind.mdb"))
strSelect = "select * from Products where productdID= "
& strprod
cmd = New OleDbCommand(strSelect, con)
con.Open()
dr = cmd.ExecuteReader()
GridView1.DataSource = dr
GridView1.DataBind()
dr.Close()
con.Close()
-----------------------------------------------------------
Use the same procedure for the authors table of pubs database
with state as Varying parameter
--------------------------------------------------------
Protected Sub btn_WriteCookies_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_WriteCookies.Click
Response.Cookies("userName").Value = txtcookie_name.Text
Response.Cookies("userName").Expires =
DateTime.Now.AddDays(1)
End Sub
-------------------------------------------------------------
If Not Request.Cookies("userName") Is Nothing Then
txtcookie_name.Text =
server.HtmlEncode(Request.Cookies("userName").Value)
txtcookie_expired.Text =
Server.HtmlEncode(Request.Cookies("userName").Expires)
End If
--------------------------------------
Protected Sub btn_deleteCookies_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_deleteCookies.Click
If Not Request.Cookies("userName") Is Nothing Then
Response.Cookies("userName").Expires =
DateTime.Now.AddDays(-1D)
End If
End Sub
----------------------------------------------------
Dim con As OleDbConnection
Dim cmd As OleDbCommand
con = New OleDbConnection("Provider=Microsoft.jet.OLEDB.4.0;
Data Source=c:\pubs.mdb")
con.Open()
cmd = New OleDbCommand(txtquery.Text.ToString, con)
GridView1.DataSource = cmd.ExecuteReader()
GridView1.DataBind()
con.Close()
INNER JOIN:
LIST RECORDS ONLY IF THERE IS A MATCHING ON BOTH SIDES.
[ WHERE CLASS ]
LEFT JOIN
LIST ALL RECORDS FROM THE LEFT TABLE , EVEN
THERE IS NO MATCHING ON RIGHT TABLE
[ ON CLASS ]
RIGHT JOIN
LIST ALL RECORDS FROM THE RIGTH TABLE , EVEN
THERE IS NO MATCHING ON LEFT TABLE
[ ON CLASS ]
SELF JOIN
A TABLE JOINS TO ITSELF IS KNOWN AS
SELF JOIN
SELECT e.EMPID , e.EMPNAME "EMPLOYEE NAME" ,
m.EMPNAME "MANAGERS NAME"
FROM EMP e , EMP m
WHERE e.MGRID = m.EMPID
------------------------------------------------------------
web configuration file
------------------------
each web page has web configuration file.
Parameters can be intialized or modified in the
web configuration file.
web configuration file is an xml file.
----------------------------------------------------------
---------------------------------------------------------
Imports System.Configuration
---------------------------------------------------------
Dim str As String = ""
Dim con As SqlConnection
Dim cmd As SqlCommand
str = ConfigurationSettings.AppSettings("constring")
con = New SqlConnection(str)
cmd = New SqlCommand("select * from emp", con)
con.Open()
GridView1.DataSource = cmd.ExecuteReader
GridView1.DataBind()
con.Close()
------------------------------------------------------------
change the web config file for the
ms-access database. display authors table
in the grid view format.
----------------------------------------------------------
-------------------------------------------------------------
Dim con As OleDbConnection
Dim cmd As OleDbCommand
Dim str As String
str = ConfigurationSettings.AppSettings("constring")
con = New OleDbConnection(str)
cmd = New OleDbCommand("select * from authors", con)
con.Open()
GridView1.DataSource = cmd.ExecuteReader
GridView1.DataBind()
con.Close()
--------------------------------------------------------------
-------------------------------------------------------------
imports system.data.oledb
imports system.data.sqlclient
imports system.configuration
-------------------------------------------------------------
Dim conaccess As OleDbConnection
Dim consqlserver As sqlconnection
Dim cmdaccess As OleDbCommand
Dim cmdsqlcommand As SqlCommand
Dim str1, str2 As String
str1 = ConfigurationSettings.AppSettings("conaccessstr")
str2 = ConfigurationSettings.AppSettings("consqlserverstr")
conaccess = New OleDbConnection(str1)
consqlserver = New SqlConnection(str2)
cmdaccess=New OleDbCommand("select * from authors", conaccess)
cmdsqlcommand=New SqlCommand("Select * from emp", consqlserver)
conaccess.Open()
consqlserver.Open()
GridView1.DataSource = cmdaccess.ExecuteReader
GridView1.DataBind()
GridView2.DataSource = cmdsqlcommand.ExecuteReader
GridView2.DataBind()
conaccess.Close()
consqlserver.Close()
---------------------- End of Connection String---------------
------------------------Break Time ---------------------------
Error Handling or Exceptional Handlings
---------------------------------------
Dim con As SqlConnection
Dim cmd As SqlCommand
con = New SqlConnection("server=localhost ;uid=sa;
pwd=dbexpert;database=dbx; Connection Timeout=15")
cmd = New sqlcommand("Select * from products" , con)
try
con.open()
gridview1.datasource = cmd.executeReader()
gridview1.databind()
con.close()
Catch
Response.write("we are sorry , Server is down ")
End try
----------------------End of Today-----------------------
Public Function CTOF(ByVal C As Double)
As double
Return (C * 1.8 + 32)
End Function
------------------------------------------------
Public Function FTOC(ByVal F As Double)
As double
Return (F - 32) / 1.8
End Function
---------------------------------------------------
Public Function TotalMarks(ByVal x As Integer,
ByVal y As Integer,
ByVal z As Integer) As Integer
Return (x + y + z)
End Function
------------------------------------------------------------
write webmethod area_circle
to find the area of circle for a given radius (r)
r is double , return value is also double
---------------------------------------------------------
use dbx
go
create table userlist
( u_id int not null identity ,
u_username varchar(25) ,
u_password varchar(25) )
----------------------------------------------------
identity is a constraint , incremented by 1
everytime , whenever we insert a record
-----------------------------------------------------
insert into userlist (u_username,u_password)
values('dbexpert' , 'abc123')
------------------------------------------------------
insert into userlist (u_username,u_password)
values('sam' , 'secret')
------------------------------------------------------
delete from userlist
--------------------------------------------------------
Dim con As SqlConnection
Dim cmd As SqlCommand
LBLmessage.Text = ""
Dim found As Integer = 0
con = New SqlConnection("server=localhost;uid=sa;pwd=dbexpert;database=dbx")
cmd = New SqlCommand("select count(*) from userlist where u_username=@name
and u_password =@pwd", con)
con.Open()
cmd.Parameters.AddWithValue("@name", txtUserName.Text)
cmd.Parameters.AddWithValue("@pwd", txtPassword.Text)
found = cmd.ExecuteScalar()
If found > 0 Then
Response.Redirect("welcome.aspx")
Else
LBLmessage.Text = "Invalid username / password"
End If
con.Close()
-----------------------------------------------------------------------
Dim con As SqlConnection
Dim cmdfound As SqlCommand
Dim cmdinsert As sqlcommand
Dim found As Integer = 0
Dim rec As Integer =0
LBLmessage.Text = ""
con = New SqlConnection("server=localhost;uid=sa;pwd=dbexpert;database=dbx")
cmdfound = new sqlcommand("select count(*) from userlist
where u_username = @name" ,con)
con.open()
cmdfound.parameters.addwithvalue("@name" , txtnewusername.text)
found = cmdfound.executescalar()
if found > 0 then
lblmessage.text ="Use Name alreay in the database ,try different name"
else
cmd = New SqlCommand("insert into userlist (u_username,u_password)
values( @name ,@pwd)", con)
cmd.Parameters.AddWithValue("@name", txtnewUserName.Text)
cmd.Parameters.AddWithValue("@pwd", txtnewPassword.Text)
rec = cmd.executeNonQuery()
if rec > 0 then
LBLmessage.Text = "Ur Name is registered "
Response.redirect("default.aspx")
End If
con.Close()
-----------------------------------------------------------------------------
Dim con As SqlConnection
Dim cmdfound As SqlCommand
Dim cmdinsert As SqlCommand
Dim found As Integer = 0
Dim rec As Integer = 0
LBLmessage.Text = ""
con = New SqlConnection("server=localhost;uid=sa;pwd=dbexpert;database=dbx")
cmdfound = New SqlCommand("select count(*) from userlist
where u_username = @name", con)
con.Open()
cmdfound.Parameters.AddWithValue("@name", txtnewusername.Text)
found = cmdfound.ExecuteScalar()
If found > 0 Then
LBLmessage.Text = "Use Name alreay in the database ,try different name"
Else
cmdinsert = New SqlCommand("insert into userlist (u_username,u_password) values( @name ,@pwd)", con)
cmdinsert.Parameters.AddWithValue("@name", txtnewusername.Text)
cmdinsert.Parameters.AddWithValue("@pwd", txtnewpassword.Text)
rec = cmdinsert.ExecuteNonQuery()
If rec > 0 Then
LBLmessage.Text = "Ur Name is registered "
Response.Redirect("default.aspx")
End If
End If
con.Close()
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