Learn ASP

ASP developed in November 1996
by Microsoft. An ASP file can
contain text, HTML tags and
scripts. Scripts in an ASP file are
executed on the server.

1. ASP stands for Active Server Pages
2. ASP is a program that runs inside IIS
3. IIS stands for Internet Information Services
4. IIS comes as a free component with Windows 2000
5. IIS is also a part of the Windows NT 4.0 Option Pack
6. The Option Pack can be downloaded from Microsoft
7. PWS is a smaller - but fully functional - version of IIS
8. PWS can be found on your Windows 95/98 CD

• Dynamically edit, change or add any
content of a Web page

• Respond to user queries or data
submitted from HTML forms

• Access any data or databases and return
the results to a browser

• Customize a Web page to make it more
useful for individual users

• The advantages of using ASP instead
of CGI and Perl, are those of simplicity
and speed

• Provide security since your ASP code
can not be viewed from the browser

• Clever ASP programming can minimize
the network traffic

ASP is a mixture of HTML and scripting
that enables you to build dynamic and database-
driven
web sites.

ASP is a server - side scripting environment
that we can use to create and run dynamic,
interactive, high - performance Web server
applications."

A server is a computer (Usually high-end, "Faster,
Bigger") that allows computers in a network to have
a shared resource.
Most servers in the area are used to

share files
to run programs
or to share Printers

The different rolls that servers play in the area are:

PDC (Primary Domain Controller)

These servers are the bosses of 1 or more servers.
All usernames and passwords are kept on the PDC.

BDC (Backup Domain Controller)

These servers are the backups which take over if the PDC fails.
They keep a copy of the Usernames and Passwords to
validate logons incase the PDC is busy.

Server
These servers are just ordinary servers that can join a domain
but can not replace a PDC like a BDC.
These servers usually are setup to just share files or printers.

Print Server
These servers are usually assigned network printers
to share and maintain.

File Servers
These servers have folders/directories shared
for access by network users.

Application Servers
These servers have programs that are shared
across the network to multiple computers.
A server can only be one of these but can be
any
combination of file, print, and
application server

A protocol is a set of rules that governs the
communications between computers
on a network.
These rules include guidelines that regulate
the following characteristics of a network
access method, allowed physical space,
types of cabling, and speed of data transfer.
The most common protocols
are:
Ethernet
Local Talk
Token Ring
FDDI
ATM

HTTP (Hypertext Transfer Protocol)
is the set of rules for transferring files
(text, graphic images, sound, video, and other
multimedia files) on the World Wide Web.
As soon as a Web user opens their Web browser,
the user is indirectly making use of HTTP.

PWS is for older Windows system
like Windows 95, 98, and NT.
PWS is easy to install and can be
used for developing and testing web
applications including ASP.

Open the Add-ons folder on your Windows98 CD,
find the PWS folder and run the setup.exe file.
An Inetpub folder will be created on your hard drive.
Open it and find the wwwroot folder.
Create a new folder, like "MyWeb", under wwwroot.
Use a text editor to write some ASP code,
save the file as "test1.asp" in the "MyWeb" folder.

Make sure your Web server is running –
The installation program has added a new icon on your task bar
this is the PWS symbol). Click on the icon and press the Start
button in the window that appears.
Open your browser and type in
http://localhost/MyWeb/test1.asp", to view your first ASP page.

Note: You cannot run ASP on Windows XP Home Edition.
Insert the Windows XP Professional CD-Rom
into your CD-Rom Drive
From your Start Button, go to Settings,
and Control Panel
In the Control Panel window select Add/Remove Programs
In the Add/Remove window select Add/Remove Windows
Components
In the Wizard window check Internet Information Services ,
click OK

An Inetpub folder will be created on your hard drive

Open the Inetpub folder, and find a folder named wwwroot

Create a new folder , like "MyWeb", under wwwroot.

Use a text editor to write some ASP code, save the file
as "test1.asp" in the "MyWeb" folder

Make sure your Web server is running - its status can be
checked by going into the Control Panel,

then Administrative Tools , and double-click
the "IIS Manager" icon

Open your browser and type
in "http://localhost/MyWeb/test1.asp", to view your first ASP page

Client/server model is a concept for describing
communications
between
computing processes that are
classified as
service consumers (clients)
and service providers (servers).

Client/server describes the relationship between
two computer programs in which
one program, the client,
makes a service request from
another program, the server,
which fulfills the request

Request

client server

Response

A scripting language has a particular
syntax used to execute commands on a
computer. A program composed of
commands from a particular scripting
language is referred to as a script.

The client, processes client side script. It is the
client’s responsibility to execute all Client-Side
scripts. Client side scripting is programmatic
code in an HTML file that runs on the
browser.
It is denoted by the <Script> tag. It is commonly
written using JavaScript Programming language
due to the fact
that Netscape support JavaScript language for
client-side scripting.

Server-side scripts are processed completely on
the web server.
The client does not receive any code from
server-side scripts; rather, the client receives just
the output of the server-side scripts.
Client-side scripts and server side scripts cannot
interact with one another because the
client – side scripts are executed on the client,
after the server-side scripts have finished
processing completely.
ASP script is a server side scripting.

In order to activate ASP components
and to use its objects, a script is placed
on the Web page along with the HTML
codes specifying how the generated
information is to be formatted for display
in the browser.
This script is written in the VBScript
language and is contained inside the
special symbols <% and %>
to indicate its presence to the server:

After you have installed IIS or
PWS follow these steps:
1. Look for a new folder called
Inetpub on your hard drive
2.Open the Inetpub folder, and
find a folder named wwwroot

3. Write some ASP code and save
the file as “first.asp" in the new
folder
4. Make sure your Web server is
running

6. Open your browser and type
"http://localhost/first.asp", to
view your first web page

Response.write command is just
like the printf command in C. The
response.write command is used
to write output to a browser. The
following example sends the text “My
First ASP Program !" to the browser:

<html>
<head>
<title>First ASP Program</title>
</head>
<body>
<%
response.write(“My First ASP
Program !")
%>
</body>
</html>

<%
response.write "Hello ASP World<br>"
response.write "Today is " & Date
response.write " and the time is " & Time
%>

ASP uses VBScript as its default
programming language. This means
VBScript comments are ASP
comments. That means there isn't any
support for multiple line comments
that you see in HTML and various
other programming languages.

 To create comment in ASP you simply place an apostrophe ‘
in front of what you want to make a comment.

 <%
 ‘This is a comment
 Response.write(“this is a comment”)
 %>

When the server invokes the ASP scripting
engine, it parse the file and inserts any
include files. It then collects the script
portion by finding all the script
delimiter.The ASP treats all non-script
contents as strings that it writes
verbatim(Exactly) back to the client. Next
the scripting engine creates variables and
external components invoked by the script.
Finally it begins the script executing each
command and sending results to the client.

Request
ASP.DLL ASP
Scripting
Engine

Response HTML
Coding Processing

Client
Server

 The process of ASP script is goes through these
five stages
1. Request: The web browser contacts the server
and tells it what page it wants to see
2. Pre-processing : The asp.dill file does some initial
processing on the requested script.
3. Execution : The scripting engine executes the
instructions in the script
4. Translate: ASP translate the result of the
execution into HTML
5. Display: The HTML is sent back to the
browser,which process the tags and display it.

•A variable is used to store information for later use.

•ASP is not a language in itself. To program ASP you
actually need to know the VBScript scripting language.
This means that all VBScript variable rules can be
applied to your ASP code.
•In ASP you declare a variable with the use of the Dim
keyword, which is short for Dimension.
•(Dimension in English refers to the amount of space
something takes up in the real world, but in
computer terms it refers to space in computer
memory.)

 The value of each variable is held in the server's
memory, so the value of the variable can be
manipulated or displayed as needed within a
page.
 In VBScript, there is only one data type, and that
is variant.
 A variant can hold either strings or numbers,
and will behave as a number if its numeric, and
as a string for string values.
 In ASP, it is not necessary to declare your
variables before using them.
 If, however, you choose to do so, you use the
DIM statement

 ASP Variable Naming Conventions
 Once again, ASP uses VBScript by default and so it
also uses VBScripts variable naming conventions.
These rules are:
1. Variable name must start with an alphabetic
character (A through Z or a through z)
2. Variables cannot contain a period
3. Variables cannot be longer than 255 characters
(don't think that'll be a problem!)
4. Variables must be unique in the scope in which it is
declared.

Assigning values in ASP is straightforward enough,
just use the equals "=" operator. Ahead we have set a
variable equal to a number and a separate variable
equal to a string.

A variable declared outside a procedure can be
accessed and changed by any script in the ASP file.
 A variable declared inside a procedure is created and
destroyed every time the procedure is executed. No
scripts outside the procedure can access or change
the variable.
 To declare variables accessible to more than one ASP
file, declare them as session variables or application
variables.

 Session Variables
 Sessionvariables are used to store information
about ONE single user, and are available to all pages
in one application. Typically information stored in
session variables are name, id, and preferences.

 Application Variables
 Application variables are also available to all
pages in one application. Application
variables are used to store information about
ALL users in one specific application.

<%
' Note that lines starting with a single quote are comments.
' Commented lines are not executed.
' First, declare variables using Dim. This is optional

Dim a, b, c, d, e, f
a=1
b=2
c= a + b
d="The value of "
e=" plus "
f=" equals "
response.write (d & a & e & b & f & c)
%>
The script output is:
The value of 1 plus 2 equals 3

Comparison operators are used when you
want to compare two values to make a
decision. Comparison operators are most
commonly used in conjunction with
"If...Then" and "While statements,
otherwise known as conditional statements.
The items that are most often compared are
numbers.
The result of a comparison operator is either
TRUE or FALSE.

A logical operator is used for complex
statements that must
make decisions based on one or more of
these truth values.

The only string operator is the string concatenation
operator "&" that takes
two strings and join them together to form a new string.
An example would be
string1 = "Tim" and string2 = " is a Hero".
The following code would combine these two strings into
one: string3 = string1 & string2

A control structure is a programming structure
that allows your program to make decisions.

Types of controls

There are three major types of controls structures

1. Conditional logic
2. Looping logic
3. Branching logic

Conditional logic allows you to match condition
if condition matches then result come if condition
not matches result not come

Example

In job selection form if age is less then 27 then you can
fill form
or
if age is more then 27 then you are not eligible for
this job.

<%

Dim Result
Result = 70

if Result >= 57 then
response.write("Pass")
else
response.write("Fail")
end if
%>

<%
Dim Result
Result = 70

if Result >= 75 then
response.write("Passed: Grade A ")
elseif Result >= 60 then
response.write("Passed: Grade B ")
elseif Result >= 45 then
response.write("Passed: Grade C ")
else
response.write("Failed ")
end if
%>

<%@ language="vbscript“%>
<%
Dim Flower
Flower = "rose"

select case flower
case "rose"
response.write(flower & " costs 20rs")
case "daisy"
case "orchild"
case else
response.write("There is no such flower in our shop")
end select
%>

ASP performs several types of repetitive operations,
called "looping".

Loops are set of instructions used to repeat the same
block of code till a specified condition returns false
or true depending on how you need it.

To control the loops you can use counter variable
that increments or decrements with each repetition
of the loop.

<%@ language="vbscript" %>
<%
For i = 0 to 10
response.write("The number is " & i &
"<br>")
Next
%>

<%@ language="vbscript" %>
<%
response.write("<h1>Multiplication table</h1>")
response.write("<table border=2 width=50>")
Dim i
For i=1 to 10
response.write("<tr>")
response.write("<td>"& i &"</td>")
Dim j
For j=2 to 43
response.write("<td>"&i * j &"</td>")
Next
response.write("</tr>")
Next
response.write("</table>")
%>

<%
Dim i
i=0
Do While i<=10
response. write( i & "<br>")
i=i+1
Loop
%>

<%
a=1
Do while a < 11
response.write "This is loop " & a & "<br>"
a=a+1
Loop
%>

<%
a=1
Do until a = 11
a=a+1
Loop
%>

<%
a=1
Do until a = 11
If a < 6 then
a=a+1
Else
Exit Do
End If
Loop
%>

 The branch logic control refers to the process of
leaving the current flow of the program to a new
set of instructions. There are two types of
branching logic controls: subroutines (procedure)
and functions. The subroutines perform actions
and functions compute values. We first start with
subroutines.

Subroutines are used to perform an
action. An example of action might
be to print a message to the screen.
When calling a VBScript or a
JavaScript procedure from an ASP
file written in VBScript, you can use
the "call" keyword followed by the
procedure name.

 Functions are written to perform calculations.
Like subroutines, functions can take one or more
arguments. Functions can also return one value.
 A function begins with the keyword function and
ends with the keyword END FUNCTION.
 FUNCTION AbValue (inNo)
If inNo < 0 then
inNo = - inNo
 END IF
AbValue = inNo
 END FUNCTION
 The value that is returned by a function can be
printed or assigned to another variable for later
use in the program.

Functions and sub procedures have many
similarities:
• They can be called or invoked from anywhere within your
script.
•A function or sub procedure can be reused as many times
as required, thus saving you time writing out repetitive
code Both are blocks of self contained code that can
accept arguments.
•Both will only run when called or invoked from code
elsewhere and will not run automatically when the page is
loaded. The difference between a function and a sub is that
a sub will do some stuff (like printing something to the
screen) and then quit, while a function runs some code
and then returns the result back to the code that called it.
•A Function could be used to do a calculation and then
return a result.

Insert the
<%@ language="language" %>
line above the <html> tag to write the
procedure/function in another scripting language:

<%@ language="javascript" %>
<%@ language=“vbscript" %>

<html>
<head>
<%
sub name()
response.write (“My name is Hunter")
end sub
%>
</head><body>
<%
response.write(“Welcome today is Monday")
response.write("<br>")
call name
response.write("thanks")
%>
</body></html>

 Vb
Scri
pt
arra
y is
0
base
d,
mea
ning
that
the
arra
y
elem
ent
inde

static array remains with fixed size throughout their life
open. To use static array you need to know upfront the
maximum number of the elements this array will
contain.
If you need more flexible vb script array
with variable index size, then you can use dynamic array.
Dynamic array index size can be increased/decreased
during their life span.

 Create static array called “arrcar” that will hold the name of
five cars.
 <%
 Dim arrcar
 arrcar=Array("Audi","Honda
city","Mercedes","Safari","Bentley")
 For I=0 to 4
 Response.write arrcar(i) & "<br>"
 Next
 %>

 Dynamic array comes in handy (Versatile) when
you aren’t sure how many items your array will
hold. To create a dynamic array you should use
the dim statement along with the array’s name,
within specifying upper bound.
<%
dim arrcar
arrcar=array()
%>
In order to use this array you need to use the
ReDim statement to define the array’s upper
bound:

 Dim arrcar
 arrcar=Array()
 Redim arrcar(27)
 If in future you need to resize this array, you should use
the redim statement again. Be very careful with the redim
statement. When you use the redim statement you lose all
the element of the array. Using the keyword PRESERVE
in conjunction with the redim statement will keep the
array we already have and increase the size.

 <%
 Dim arrcar
 Arrcar=array()
 Redim arrcar(27)
 Redim PRESERVE arrcar(52)
 %>

 <%
 Dim arrcar
 redim arrcar(3)
 arrcar=Array("Audi","Honda
city","Mercedes","Safari","Bentley","lemo","alto")
 redim preserve arrcar(7)
 For i=0 to 6
 Response.write arrcar(i) & "<br>"
 Next
 %>

 Array don’t have to be a simple list of keys and
values, each location in the array can hold another
array. The reason you may use this type of array is
when you have records of each item.
 For example car,year,price,……

and you want to display one record at a time.
The most commonly used are two-
dimensional arrays.You can thin of two
dimensional array as a matrix, or grid , with width
and height of rows and columns. Here is

 how you could define two-dimensional array and display the
array values on the web page.
 <%
 dim arrcar(2,4)
 arrcar(0,0)="honda city"
 arrcar(1,0)="2009"
 arrcar(2,0)="859598"

 arrcar(0,1)="audi"
 arrcar(1,1)="2009"
 arrcar(2,1)="450000"

 arrcar(0,2)="honda city"
 arrcar(1,2)="2009"
 arrcar(2,2)="700000"

 arrcar(0,3)="safri"
 arrcar(1,3)="2009"
 arrcar(2,3)="6,00000"

 arrcar(0,4)="lemo"
 arrcar(1,4)="2009"
 arrcar(2,4)="990000"

 response.write ("<table border=2>")
 response.write ("<tr> <td>row</td><td>car</td>
<td>year</td> <td>price</td> </tr>")
 for i=0 to ubound (arrcar,2)
 response.write ("<tr> <td>" & i & "</td>")
 response.write("<td>" & arrcar (0,i) & "</td>")
 next
 response.write("</table>")
 %>

 dim a(1,1)
 a(0,0)="HTML"

 a(0,1)="Hyper Text Markup Language“

 a(1,0)="ASP"

 a(1,1)="Active Server Page“

 for i=0 to ubound(a,1)

 response.write("<table width=60% ><tr><td>")

 response.write(a(0,i)& "</td><td>")

 response.write(a(1,i)&"</td></tr>")

 next

 response.write("</table>")

Vb script is client side script
language and run on client side so
we do not require server and asp.
It is lighter because no load at
server it completely run at client
side because all codes written in
html.

Conversion of one data type to another is called type
casting
Cint
Cdate
Asc

 ASC
 <%
 response.write("ANSI code of a string is: " &
asc("a"))
 %>
 Cdate
 converts the date expression to the variant of
subtype date
 <%
 a="march 14,1985"
 response.write ("<br>" & cdate(a))
 %>

 Cint
 Converts an expression to a variant of subtype
Integer.
 <%
 Response.write(Cint(2314.166))
 %>

 Date
 <%
 response.write("current date of the system:“ & date)
 %>
 Time
 <%
 response.write(“Current time of the system" & time)
 %>
 Day
 <%
 response.write(“day of the system: " &day(date))
 %>

 WeekDayName
 <%
 response.write(“Name of the weekday :" &
weekdayname(1))
 %>
 WeekDay
 <%
 response.write("week day : " & weekday(date))
 %>
 Month
 <%
 response.write("<br> month" &month(date))
 %>

 MonthName
 response.write(“Name of the month“ &
monthname(3))
 Year
 <%
 response.write("year:“ & year(date))
 %>

 DateDiff
 <%
 response.write("day" &
datediff("d",date,“01/01/2000"))
 response.write("<br> Year" & datediff("yyyy",date,"
01/01/2000"))
 response.write("<br> month" & datediff("m",date,"
01/01/2000"))
 response.write("<br> Mintue" & datediff("n",date,"
01/01/2000 "))
 response.write("<br> hour" & datediff("h",date,"
01/01/2000 "))
 response.write("<br> second" & datediff("s",date,"
01/01/2000"))
 %>

1. Abs function
 The Abs function returns the absolute value of a
specified number.
 Example
 <%
 Response.write (Abs(1) & “<br>”)
 Response.write(Abs(-1))
 %>

 Cos Function
 The cos function returns the cosine of a specified number.

 <%
 Response.write(cos(50.0))
 %>

 Exp Function
 The Exp function returns e raised to a power.
 <%
 Response.write(exp(6.7))
 %>

 IntFunction
 The int function returns the integer part of a
number
 <%
 Response.write(int(6.83227))
 %>

 Sqr Function
 The sqr function returns the square root of a
number.
 <%
 Response.write(sqr(9))
 %>
 Tan Function
 The tan function returns the tangent of a number
< %
 Response.write(tan(59))
 %>

The InStr function returns the position
of the first occurrence of one string
within another.
<%
dim a,b
a="Have a Great Day Enjoy"
b=instr(a,"Great")
response.write(b)
%>

Output:8

The InStrRev function returns the position
of the first occurrence of one string within
another. The search begins from the end of
string, but the position returned counts from
the beginning of the string
<%
dim a,b
b=instrrev(a,"Day")
response.write(b)
%>
Output:14

The LCase function converts a
specified string to lowercase.

dim a
a=“HAVE A GREAT DAY!"
response.write(LCase(a))

Output: have a great day!

The Left function returns a specified
number of characters from the left
side of a string.

dim a
a="This is a beautiful day!"
response.write(Left(a,11))

Output:This is a b

The Len function returns the number of
characters in a string.

dim a
response.write(Len(a))

Output:24

The Mid function returns a specified
number of characters from a string.

<%
dim a
b=mid(a,8,9)
response.write(b)
%>

Output: Great Day

The Replace function replaces a specified
part of a string with another string a
specified number of times

dim a
response.write(Replace(a,"beautiful","horrible"))

Output:This is a horrible day!

The String function returns a string
that contains a repeating character
of a specified length.

response.write(String(10,"#"))
Output:##########

 An object is a thing or an entity like pen, table,
chair, mobile phone, car etc. in other words, an
object is a reusable component that contains
related data and functions that represent some
real-life things.
 A property is a basic characteristics of an object
or you can say property is a value that describe the
object, like color, shape etc.
 A method is something you can do with the
object. In other words, method is a function which
can be performed on the object. For example:
1. Pen is used for writing.
2. Chair is used for sitting.

Active Server Pages consist of six built in objects.
They are ready made objects which provide
functionality to your web pages without requiring
you to make custom objects

Following are the six built in ASP objects :

1. Application
2. ASP Error
3. Request
4. Response
5. Server
6. Session

A group of ASP files that work
together to perform some purpose
is called an application.

ASession object stores information
about, or change settings for a user
session. Only store SMALL amounts
of data in session variables!

 The Response object is used to send the output back to
the client (browser). It includes all the HTTP variables,
cookies that will be stored on the client browser and other
info about the content being sent

The Request object makes available all the values that client
browser passes to the server during an HTTP request. It
includes client browser info, cookie details ( of this
domain only ), client certificates ( if accessing through
SSL ) etc.

The ASPError object, implemented
in ASP 3.0, contains detailed
information about the last error
that has occurred.

 An application on the Web may consists of
several ASP files that work together to
perform some purpose. The Application
object is used to tie these files together.
 The Application object is used to store and
access variables from any page, just like the
Session object. The difference is that ALL
users share ONE Application object (with
Sessions there is ONE Session object for
EACH user).

The Application object holds
information that will be used by many
pages in the application (like database
connection information). The
information can be accessed from any
page. The information can also be
changed in one place, and the changes
will automatically be reflected on all
pages.

Store and Retrieve Application
Variables
Application variables can be
accessed and changed by any page
in an application.
You can create Application
variables in "Global.asa"

Store and Retrieve Application Variables

Application variables can be accessed and changed
by any page in the application.

You can create Application variables in "Global.asa"

<script language="vbscript" runat="server">
Sub Application_OnStart
application(“cname")=“ infosys delhi "
End Sub
</script>

The Global.asa file is an optional file
that can contain declarations of objects,
variables, and methods that can be
accessed by every page in an ASP
application.
All valid browser scripts (JavaScript,
VBScript, PerlScript, etc.) can be used
within Global.asa.

The Global.asa file can contain only
the following:
Application events
Session events
<object> declarations
Type Library declarations
the #include directive
Note: The Global.asa file must be
stored in the root directory of the ASP
application, and each application can
only have one Global.asa file.

In Global.asa you can tell the application
and session objects what to do when the
application/session starts and what to
do when the application/session ends.
The code for this is placed in event
handlers. The Global.asa file can contain
four types of events:

Application_OnStart - Occurs when
the FIRST user calls the first page in an
ASP application. This event occurs after
the Web server is restarted or after the
Global.asa file is edited. The
"Session_OnStart" event occurs
immediately after this event.
Session_OnStart - This event occurs
EVERY time a NEW user requests his or
her first page in the ASP application.

Session_OnEnd - This event occurs
EVERY time a user ends a session. A
user-session ends after a page has not
been requested by the user for a specified
time (by default this is 20 minutes).
Application_OnEnd - This event
occurs after the LAST user has ended the
session. Typically, this event occurs when
a Web server stops. This procedure is
used to clean up settings after the
Application stops, like delete records or
write information to text files.

<script language="vbscript"
runat="server">
sub Application_OnStart
'some code
end sub
sub Application_OnEnd
'some code
end sub
sub Session_OnStart
'some code
end sub

sub Session_OnEnd
'some code
end sub

</script>

Because we cannot use the ASP script
delimiters (<% and %>) to insert
scripts in the Global.asa file, we put
subroutines inside an HTML <script>
element.

In this example we will create a
Global.asa file that counts the
number of current visitors.
The Application_OnStart sets the
Application variable "visitors" to 0
when the server starts
The Session_OnStart subroutine
adds one to the variable "visitors"
every time a new visitor arrives

The Session_OnEnd subroutine
subtracts one from "visitors" each
time this subroutine is triggered
The Global.asa file:
<script language="vbscript"
runat="server">

Sub Application_OnStart
Application("visitors")=0
End Sub

Sub Session_OnStart
Application.Lock
Application("visitors")=Application("visit
ors")+1
Application.UnLock
End Sub
Sub Session_OnEnd
Application.Lock
Application("visitors")=Application("visit
ors")-1
Application.UnLock
End Sub
</script>

To display the number of current
visitors in an ASP file:
<html>
<head>
</head>
<body>
<p>There are <
%response.write(Application("visit
ors"))%> online now!</p>
</body>
</html>

The Global.asa file is contain declarations
of objects, variables, and methods that can be
accessed by every
page in an ASP application. All valid browser scripts
(JavaScript, VBScript, PerlScript, etc.)
can be used within Global.asa.

The ASP Server object is used to access properties
and methods on the server. Its properties and methods
are described below:
Properties
Script Timeout
Sets or returns the maximum number of seconds a
script can run before it is terminated

Methods
Create Object
Creates an instance of an object
Execute
Executes an ASP file from inside another ASP file

GetLastError()
Returns an ASP Error object that describes the error
condition that occurred
HTMLEncode
Applies HTML encoding to a specified string
<%
= Server.HTMLEncode("The paragraph tag: <P>")
%>

MapPath
Maps a specified path to a physical path
<%
=Server.MapPath(Request.ServerVariables("PATH_INFO"))
%>
Transfer
Sends (transfers) all the information created in one
ASP file to a second ASP file
URLEncode
Applies URL encoding rules to a specified string

ASession object stores information
about, or change settings for a user
session. Only store SMALL amounts of
data in session variables!

When you are working with an application
on your computer, you open it, do some
changes and then you close it. This is
much like a Session.
The computer knows who you are. It
knows when you open the application and
when you close it.
 Variables stored in a Session object hold
information about one single user, and are
available to all pages in one application.

 Common information stored in
session variables are name, id, and
preferences.
The server creates a new Session
object for each new user, and destroys
the Session object when the session
expires.

A session starts when:
A new user requests an ASP file, and the
Global.asa file includes a Session_OnStart
procedure
A value is stored in a Session variable
A user requests an ASP file, and the
Global.asa file uses the <object> tag to
instantiate an object with session scope

The most important thing about the
Session object is that you can store
variables in it.
The example ahead will set the
Session variable username to
“Shawn" and the Session variable age
to “30":

<%
Session("username")=“Shawn"
Session("age")=30
%>

When the value is stored in a session
variable it can be reached from ANY
page in the ASP application:
Welcome
<%
Response.Write(Session("username")
)
%>
The line above returns: "Welcome
Shawn".

The Contents collection contains all
session variables.
The example ahead removes the
session variable "sale" if the value of
the session variable "age" is lower
than 18:

<%
If Session.Contents("age")<18 then
Session.Contents.Remove("sale")
End If
%>
To remove all variables in a session, use
the RemoveAll method:
<%
Session.Contents.RemoveAll()
%>

Properties
SessionID

The SessionID is a read-only property that uniquely
identifies each current user's session. Each session has
a unique identifier that is generated by the server when
the session is created and stored as a cookie on the
client machine.
TimeOut

The Timeout property sets or returns the timeout period
(in minutes) for thе Session object in this application.
If the user does not refresh or request a page within the
timeout period,the session ends. Can be changed in
individual pages as required.

Acookie is often used to identify a
user.

Acookie is often used to identify a
user. A cookie is a small file that the
server embeds on the user's
computer. Each time the same
computer requests a page with a
browser, it will send the cookie too.
With ASP, you can both create and
retrieve cookie values.

The "Response.Cookies" command is
used to create cookies.
The Response.Cookies command
must appear BEFORE the <html>
tag.

IN THE EXAMPLE BELOW, WE WILL
CREATE A COOKIE NAMED
"FIRSTNAME" AND ASSIGN THE
VALUE "ALEX" TO IT:

<%
Response.Cookies("firstname")="Alex"
%>

IT IS ALSO POSSIBLE TO ASSIGN
PROPERTIES TO A COOKIE, LIKE
SETTING A DATE WHEN THE COOKIE
SHOULD EXPIRE:
<%
Response.Cookies("firstname")="Alex
Response.Cookies("firstname").Expires
=#May 10,2012#
%>

The"Request.Cookies"
command is used to retrieve a
cookie value

IN THE EXAMPLE BELOW, WE
RETRIEVE THE VALUE OF THE COOKIE
NAMED “FIRSTNAME" AND DISPLAY IT
ON A PAGE:
<%
fname=Request.Cookies("firstname")
response.write("Firstname=" &
fname)
%>

Form
 Forms are a convenient way to communicate with
visitors to your Web site.
 A form on a page allows a user to enter data that
is sent to a server for processing

 The <form> tag is used to create an HTML
form for user input.
 A form can contain input elements like text
fields, checkboxes, radio-buttons, submit
buttons and more. A form can also contain
dropdown list, textarea elements.
 Forms are used to pass data to a server.

Attributes oF Form

 Action = Specifies where to send the form-data when a
form is submitted
 Value =“url”

 Method = Specifies how to send form-data

 Value = “get or post”

 Name = Specifies the name for a form

Controls

 Users interact with forms through named
controls.
 Each control has both an initial value and a
current value, both of which are character
strings.

Control types

 The Input Element
 The most important form element is the input
element.
 The input element is used to select user
information.
 An input element can vary in many ways,
depending on the type attribute. An input
element can be of type text field, checkbox,
password, radio button, submit button, and
more.

 Text Fields
 <input type="text">
 defines a one-line input field that a user can
enter text into it.
 E.G.
 <form>
First name: <input type="text"
name="firstname">
Last name: <input type="text"
name="lastname">
</form>

 Password Field
 <input type="password">
 defines a password field:
 E.G.
 <form>
Password: <input type="password"
name="pwd" />
</form>

 Radio Buttons
 <input type="radio">

 defines a radio button. Radio buttons let a user select
ONLY ONE one of a limited number of choices:
 E.G

 <form>
<input type="radio" name="sex" value="male"> Male
<input type="radio" name="sex" value="female"> Female
</form>

 Checkboxes
 <input type="checkbox">
 defines a checkbox. Checkboxes let a user
select ONE or MORE options of a limited
number of choices.
 E.G.
 <form>
<input type="checkbox" name="v1"
value="Bike" /> I have a bike<br />
<input type="checkbox" name="v2"
value="Car" /> I have a car
</form>

 Submit Button
 <input type="submit">
 defines a submit button.
 A submit button is used to send form data to a server. The
data is sent to the page specified in the form's action
attribute. The file defined in the action attribute usually does
something with the received input:
 <form name="input" action=“a.asp" method="get">
Username: <input type="text" name="user" />
<input type="submit" value="Submit" />
</form>

Pull down Lists: It is used to select one choice out of many
choices. This control is very useful when we have number of
choices and we have to choose only one particular choice.
These lists occupy minimum amount of space. We use the
<select> tag for this.
 Syntax
 <select name=”unique_name” size=”n”>
 <option value=”any_value”>
 <option value=”any_value ”>
 </select>

 <html>
<head><title>Asking for information</title></head>
<body>
<form method="post" action="form_response.asp">
Your name: <input type="text" name="name"
size="20"><BR>
Your email: <input type="password" name="email"
size="15"><BR>
<input type="Submit" value="Submit">
</form>
</body>
</html>

 <html>
<head><title>Responding to a form</title></head>
<body>
Your name is <% =Request.Form("name") %> <BR>
Your email is <% =Request.Form("email") %>
</body>
</html>

The Response object is used to send the output back
to the client (browser). It includes all the HTTP
variables, cookies that will be stored on the client
browser and other info about the content being
sent.

Redirect Redirects the browser to another
page (URLe.g.Response.Redirect
"http://www.gurchet.orgfree.com".

Write Writes the specified string to the
web page e.g. Response.Write
"Hello World!".

The Request object makes available all the values that
client browser passes to the server during an HTTP
request. It includes client browser info, cookie details ( of
this domain only ), client certificates ( if accessing
through SSL ) etc.

Form
Collection of all the values of
Form element in the HTTP
request.

QueryString

Collection of variables which are stored in the HTTP query
string. Name / value pairs can also be appended to the URL
after the end of page name e.g.
"http://www.stardeveloper.com/asp_request.asp?
author=Faisal+Khan" contains one variable 'author' with a
value of 'Faisal Khan'.

Caching is a well known concept in computer science:
when programs continually access the same set of
instructions, a massive performance benefit can be
realized by storing those instructions in RAM.
This prevents the program from having to access the
disk thousands or even millions of times during execution
by quickly retrieving them from RAM. Caching on the
web is similar in that it avoids a roundtrip to the origin
web server each time a resource is requested and
instead retrieves the file from a local computer's browser
cache or a proxy cache closer to the user.

The Buffer property specifies whether to buffer
the output or not. When the output is buffered, the
server will hold back the response to the browser
until all of the server scripts have been
processed, or until the script calls the Flush or
End method.

Note: If this property is set, it should be before
the <html> tag in the .asp file

response.Buffer[=flag]

Response.clear
Response.Flush
Response.End

For Communicating With User We Use Forms
In Form We Have Two Method For
Communicating User
1. Method Post
2. Method Get

Form tag provide various form fields for sending
information to server. And we use these fields
to communicating. Like text field to send mails

Another <form> tag attribute specifies how the
information will be sent to wherever it's going. That's the
"method" attribute. The method attribute is either
method="POST"
or
method="GET"
Which you use depends on how the destination program
or function wants to receive the information.

Sending With Method GET
method="GET" is used if you want to send
information somewhere via a browser URL.
You've seen URLs that send information; they
look something like:
http://gurchet.orgfree.com/handler.name?
color=red&shape=round
In the above URL, the part after the question
mark is information sent to handler.name.
Multiple information chunks are separated with
an ampersand. The GET method can send only a
limited amount of information. The limitation
depends on the server where the current web
page is on and the server where the information
is sent to. The limitation can be as little as 256
bytes but is often 1k or more.

Sending With Method POST
method="POST" is the most common method
used to send information from a form to an
information processing program or function.
This is the method used when sending form
information to JavaScript functions. Most CGI
programs are written to accept information with
the POST method, some to accept only the
POST
method. The POST method can send much more
information than the typical GET method.
Currently, most browsers and servers limit the
amount of POST information to about 32k. With
POST, the information is not sent via the URL.
The sending is invisible to the site visitor.

Accessing the HTTP Headers
Standard HTTP Headers
Environment Variables
Using Cookies
Advantages & disadvantages cookies

When the client request a web page from the server it
not only sends the url of web page requested but also
send some additional information this extra
information consists of useful facts about the client

1. What browser is being used
2. What operating system the client running
3. What url the user just come from

These information are called request header

Request Header is a single line of text that your
browser sends to the web Server when requesting to
view any web page.
Response Header when the server sends back the
requested web page to the client it also sends a set
of headers known as response headers.

Both request headers and response headers are
called HTTP Header

An HTTP Header is a single piece of information
sent either from client To the server when
requesting a page or from the server to the client
when Responding to a page request.

1. HTTP_ACCEPT
2. HTTP_ACCEPT_LANGAGUE
3. HTTP_CONNECTION
4. HTTP_HOST
5. HTTP_USER_AGENT
6. HTTP_REFERER
7. HTTP_COOKIE

The HTTP Headers are useful for obtaining
information about current Visitor but tell you nothing
about the web server or asp page that is being
requested by the client. To obtain such information
we use web server’s Environment Variables
Environment Variables are bit of information that web
browser make available to any Program that requested
them.
It contain information such as:-

1. Name of web server
2. url currently processing asp page
3. Name of software being used by web server.

1. URL
2. PATH_INFO
3. PATH_TRANSLATED
4. APPL_PHYSICAL_PATH
5. QUERY_STRING
6. SERVER_NAME
7. SERVER_SOFTWARE

Many environment variables do not contain a value because it use when
required for example CERT Variable contains empty strings as their value.
This is because these variable are Used only when client and server use
CERTIFICATES .When a browser and web Server communicate over a
secure channel, certificates are used to ensure the identity of the Client to
the server.

Cookies are small amount of information stored in client
computer for some time.
When cookies are created on the client computer the developer
need to specify when they expire. After a cookie expire it will
automatically remove itself from the client computer.
Cookies created response.cookies(“user”)=“John”
Cookies read request.cookies(“user”)
Cookies expire response.cookies(“user”).expires=date+10

1. Cookies stores on client computer so not need more space
in web server
2. Save small amounts of information for very long periods of
time
3. It is used to customize a user visit to your web site

1. User can choose not to accept cookies on their web
browser
2. It not save large amount to date
3. It save only string, date or numeric date
4. It is not secure because if temp folder deleted it also
delete all cookies

1. Web is stateless ?
2. Why to maintain state ?
3. Session Object
4. Asp application object
5. Asp global.asa file
6. Events in global.asa

An application is said to have state if it persists
information for each user. In a web site this is not
the case for example if you fill out s form on A web
page and then revisit the form at some time later
the form fields will not contain The valued you entered
earlier because web site lack state this is called
stateless

For maintaining state asp provides many ways
these ways are used to kept information
Which is used in round tripping process.

In asp we have build in objects and collection for
maintaining state

Session object and application objects are used for
this purpose,
cookies are also used to Maintain state

PITFALLS OF SESSION VARIABLES
(DRAWBACKS)

If user select that his system not save session then session not work
Default time is 20 minute it is also big disadvantages

The ASPError object, implemented in ASP 3.0, contains detailed information
about the last error that has occurred.
This information can only be accessed through the Server.GetLastError.
The ASPError object has nine read-only properties and no methods.
Properties
•ASP Code
This property returns the error code generated by IIS.
•Description
The description property returns the short description of the error.
•ASP Description
Returns a string that contains more detailed error information than the
Description property, but it is not available for all errors.

There are 3 main types of errors:

Compile-time errors

These errors are usually in the syntax
of the code and stop the ASP from
compiling. You may have experienced
this if you left the closing ”Next”
statement off of a “For” loop.

Runtime errors

These happen when you try to execute
the ASP page. For example, if you try
setting a variable outside its allowed
range.

Logic errors
Logic errors are harder to detect.
The problem lies within the structure of
the code, and the computer cannot detect
an error. These types require thorough
testing before rolling out the application.

5- invalid procedure call
6- overflow
7- out of memory
11- division by zero
13- type mismatch
53- internal error
61- disk full
76- path not found
438- object not support method or property
424- object required

<%

On Error Resume Next
X = 15
Y=5
Z = 15

Response.Writes( X/Y & "<b><br>")
Response.Write( X/Z & "<b><br>")

If Err.Number = 0 Then
response.write("no error")
else
Response.Write(err.number & "<br>")
Response.Write(err.description)
End If
%>

Non Asp Error

Error Created By Server Is Called Non Asp Error
In This type Of Error Program Is Not Executated
Because Server Creates Problem.
Some Time Message Come – Server Not Exist Or
File Not Found

database:
A collection of related information stored
in a structured format.
Database is often used interchangeably
with the term table
A table is a single store of related
information; a database can consist of
one or more tables of information that are
related in some way.

data entry:
The process of getting information into a
database, usually done by people typing
it in by way of data-entry forms designed
to simplify the process.

dbms: Database management system.
A program which lets you manage
information in databases.
Lotus Approach, Microsoft Access and
FileMaker Pro, for example, are all DBMSs,
although the term is often shortened to
'database'. So, the same term is used to
apply to the program you use to
organise your data and the actual
data structure you create with that program.

field:
Fields describe a single aspect of
each member of a table.
A student record, for instance, might
contain a last name field, a first name field,
a date of birth field and so on. All records
have exactly the same structure, so they
contain the same fields. The values in each
field vary from record to record, of course.
In some database systems, you'll find fields
referred to as attributes.

flat file:
A database that consists of a single table.
Lightweight database programs such as
the database component in Microsoft Works
are sometimes called 'flat-file managers‘
(or list managers) because they can only
handle single-table databases. More powerful
programs, such as FileMaker Pro, Access,
Approach and Paradox, can handle
multi-table databases, and are
called relational database managers,
or RDBMSs.

primary key:
A field that uniquely identifies a record in
a table. In a students table, for instance,
a key built from last name + first name
might not give you a unique identifier
(two or more Jane Does in the school,
for example). To uniquely identify each
student, you might add a special Student
ID field to be used as the primary key.

foreign key:
A key used in one table to represent the
value of a primary key in a related table.
While primary keys must contain unique
values, foreign keys may have duplicates.
For instance, if we use student ID as the
primary key in a Students table
(each student has a unique ID),
we could use student ID as a foreign key
in a Courses table: as each student may
do more than one course,

index:
A summary table which lets you quickly look
up the contents of any record in a table.
Think of how you use an index to a book:
as a quick jumping off point to finding full
information about a subject. A database
index works in a similar way. You can create
an index on any field in a table

SQL: Structured Query Language
(pronounced sequel
in the US; ess-queue-ell elsewhere).
A computer language designed to organize
and simplify the process of getting information
out of a database in a usable form, and also
used to reorganize data within databases.
SQL is most often used on larger databases
on minicomputers, mainframes and
corporate servers.

query:
A view of your data showing information
from one or more tables. For instance,
using the sample database we used when
describing normalisation, you could query
the Students database asking "Show me the
first and last names of the students
Whose roll no is 90821.

RDBMS: Relational database management
system.
A program which lets you manage
structured information
stored in tables and which can
handle databases
consisting of multiple tables.

RECORD:
A record contains all the information
about a single 'member' of a table. In a
students table, each student's details
(name, date of birth, contact details,
and so on) will be contained in its own
record.

RELATIONAL DATABASE:
A database consisting of more than
one table. In a multi-table database,
you not only need to define the structure
of each table, you also need to define
the relationships between each table
in order to link those tables correctly.

REPORT:
A form designed to print information from a
database (either on the screen, to a file or
directly to the printer).

TABLE: A single store of related information.
A table consists of records, and each
record is made up of a number of fields.
Just to totally confuse things, tables are
sometimes called relations. You can think
of the phone book as a table: It contains a
record for each telephone subscriber, and
each subscriber's details are contained
in three fields - name, address and telephone.

Dr. E.F. Codd, an IBM researcher,
first developed the relational data model in 1970.
In 1985, Dr. Codd published a list of 12 rules that
concisely define an ideal relational database,
which have provided a guideline for the design
of all relational database systems ever since.

Rule 1: The Information Rule
All data should be presented to the
user in table form

Rule 2: Guaranteed Access Rule
All data should be accessible without
Ambiguity (doubt). This can be accomplished
through a combination of the table name,
primary key, and column name.

Rule 3:
Systematic Treatment of Null Values
A field should be allowed to remain empty.
This involves the support of a null value,
which is distinct from an empty string
or a number with a value of zero. Of course,
this can't apply to primary keys. In addition,
most database implementations support the
concept of a nun- null field constraint that
prevents null values in a specific table column.

Rule 4:
Dynamic On-Line Catalog Based on the
Relational Model

A relational database must provide access
to its structure through the same tools that
are used to access the data. This is usually
accomplished by storing the structure definition
within special system tables.

Rule 5:
Comprehensive Data Sublanguage Rule
The database must support at least one
clearly defined language that includes
functionality for data definition, data
manipulation, data integrity, and database
transaction control. All commercial
relational databases use forms of the
standard SQL (Structured Query Language)
as their supported comprehensive language.

Rule 6: View Updating Rule
Data can be presented to the user in different
logical combinations, called views. Each
view should support the same full range
of data manipulation that direct-access
to a table has available. In practice,
providing update and delete access to
logical views is difficult and is not fully
supported by any current database.

Rule 7:
High-level Insert, Update, and Delete
Data can be retrieved from a relational
database in sets constructed of data
from multiple rows and/or multiple tables.
This rule states that insert, update, and delete
operations should be supported for any
retrievable set rather than just for a single
row in a single table

Rule 8: Physical Data Independence
The user is isolated from the physical
method of storing and retrieving information
from the database. Changes can be made
to the underlying architecture
( hardware, disk storage methods )
without affecting how the user accesses it.

Rule 9: Logical Data Independence
How a user views data should not change
when the logical structure (tables structure)
of the database changes. This rule is particularly
difficult to satisfy. Most databases rely on strong
ties between the user view of the data and the
actual structure of the underlying tables.

Rule 10: Integrity Independence
The database language (like SQL)
should support constraints on user input
that maintain database integrity. This
rule is not fully implemented by most
major vendors. At a minimum, all
databases do preserve two constraints
through SQL.
No component of a primary key can
have a null value. (see rule 3)
If a foreign key is defined in one table,
any value in it must exist as a primary
key in another table.

Rule 11: Distribution Independence
A user should be totally unaware of whether
or not the database is distributed (whether parts
of the database exist in multiple locations).
A variety of reasons make this rule difficult to
implement;

Rule 12: Nonsubversion Rule
There should be no way to modify the
database structure other than through the
multiple row database language (like SQL).
Most databases today support administrative
tools that allow some direct manipulation of
the datastructure.

1.What is ADO?
ADO is a Microsoft technology
ADO stands for ActiveX Data Objects
ADO is a Microsoft Active-X component
ADO is automatically installed with
Microsoft IIS
ADO is a programming interface to access
data in a database

2.Accessing a Database from an ASP Page
The common way to access a database from
inside an ASP page is to:
Create an ADO connection to a database
Open the database connection
Create an ADO recordset
Open the recordset
Extract the data you need from the recordset
Close the recordset
Close the connection

3. How DSN-less Database Connection Created ?

The easiest way to connect to a database is to use
a DSN-less connection. A DSN-less connection can be
used against any Microsoft Access database on your
web site.
If you have a database called "northwind.mdb" located
in a web directory like "c:/webdata/",
you can connect to the database with the following
ASP code:
<%
set conn=Server.CreateObject("ADODB.Connection")
conn.Provider="Microsoft.Jet.OLEDB.4.0“
conn.Open "c:/webdata/northwind.mdb"
%>

4. What is Connection Object ?
The ADO Connection Object is used to create
an open connection to a data source. Through
this connection,you can access and manipulate
a database.If you want to access a database
multiple times,you should establish a
connection using the Connection object. You
can also make a connection to a database by
passing a connection string via a Command or
Recordset object. However,this type of
connection is only good for one specific, single
query.
set objConnection=Server.CreateObject("ADODB.connection")

5. What is Recordset Object ?

The ADO Recordset object is used to hold a set of records
from a database table. A Recordset object consist of
records and columns (fields).

In ADO, this object is the most important and the one
used most often to manipulate data from a database.

set objRecordset=Server.CreateObject("ADODB.recordset")

7. How Data is Extracted from Record set

After a record set is opened, we can extract data from
record set.
Suppose we have a database named "North wind",
we can get access to the
"Customers" table inside the database
<%
dim con
set con=Server.createObject("ADODB.connection")
con.open "provider=microsoft.jet.oledb.4.0;Data source="& server.
mappath("db1.mdb")
set rs=Server.createObject("ADODB.Recordset")
q="select * from stu"
rs.open q,con
response.write("<table border=3 align=center height=30% width=20% >
"&"<tr><th>")
response.write("ID" & "</td><td>" & "<b> Name"& "</td><td>" & "<b>
Marks")

response.write("</td></tr>")
do while not rs.EOF
response.write("<tr><td>")
response.write(rs("id")&" " & "</td><td>")
response.write(rs("name")&" " & "</td><td>")
response.write(rs("marks")&" " & "</td>")
response.write("</tr>")
rs.movenext
loop
%>

 Recordset Object
 The ADO Recordset object is used to hold a set of records
from a database table. A Recordset object consist of
records and columns (fields).
 In ADO, this object is the most important and the one
used most often to manipulate data from a database.

What is Recordset updating:
Immediate updating - all changes are
written immediately to the database
once you call the Update method.

Batch updating - the provider will cache
multiple changes and then send them
to the database with the Update
Batch method.

12. Define 4 different types of cursor in ADO

Cursor:
Database cursor is a control structure that enables traversal
over the records in a database. Cursors are used by database
programmers to process individual rows returned by database
system queries.

Types Of Cursor
Dynamic cursor –
Allows you to see additions, changes,
and deletions by other users.

Keyset cursor –
Like a dynamic cursor, except that you cannot
see additions by other users, and it prevents access
to records that other users have deleted.

Static cursor
Provides a static copy of a recordset for you to
use to find data or generate reports. Static cursors
Support scrolling backward and forward, but they
do not support updates.This is the only type of cursor
allowed when you open a client-side Recordset object.
The following is an example of how to obtain a static
cursor by using ADO.NET:
cmd.CommandText = "Select * from tablename";
SqlCeResultSet rs = cmd.ExecuteResultSet
(ResultSetOptions.Scrollable | ResultSetOptions.
Insensitive);

Forward-only cursor

-Allows you to only scroll forward through the
Recordset.
-Additions, changes, or deletions by other users will
not be visible.

Popular Relational Database Product

SQL 7
ORACLE8
SYSBASE
IBM’S DB2
INFORMIX

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