Server Side Programming ASP1 Server Side Programming Database Integration Peter O’Grady.

Server Side Programming ASP 1

Server Side ProgrammingDatabase Integration

Peter O’Grady


Content

Introduction Server Side Programming (ASP) Database Integration


Introduction Internet allows for client-server systems Programs can be invoked on either/both

clients and servers:– Client side includes Java Applets, ActiveX

components with JScript or VBScript.– Server side includes CGI and ASP

Data can be kept on servers distributed across network and accessed via client (topic of this portion of course)


Why use Internet to access data? People can access the data using a familiar

browser interface. No special software required.

Data can be maintained centrally or distributed.

Data can be integrated with other information in an institution’s web pages

Information can be made available to anyone (with permission) on the Internet


How can database be accessed by web browser?

Web browser Web browser

Web browser

Server Side Programminge.g. Microsoft IIS server :

ASP (VBScript, JScript, SQL)

Internet

Database


Client Side Scripts They are browser-specific, so the same code may

be interpreted differently depending on the browser being used. (Note recent use of ECMAScript as general JScript or JavaScript)

They can't be used to refer to a database (such as a product catalog).

They can lessen the burden on server and are particularly useful for such tasks as validating data before sending to server side to be processed.


Server Side Programming (ASP)


Content

Server Side programming overview Example

– Microsoft Internet Information Services (IIS)– Active Server Page(ASP)– VBScript/JScript


Common Gateway Interface (CGI) CGI Is a standard for interfacing

external applications with web servers (Common Gateway Interface, 1995).

Involves a new process each time it is invoked therefore can be slow with multiple users.

Alternatives: ISAPI (ASP), NSAPI.


IIS

IIS is a web server that runs on Win NT, 2000, Server2003 and XP Server.

Can use component-based (COM/ActiveX) client/server applications as well as JScript (ECMAScript) and VBScript


What is ASP?

"a server - side scripting environment that you can use to create and run dynamic, interactive, high - performance Web server applications”. Microsoft

Can include COM/ActiveX components and/or compiled code

Runs on IIS


What are Active Server Pages?

Server-side environment Can provide compile-free application

environment Combine HTML, scripts, COM and

ActiveX server components.


Using ASP User usually completes HTML form in a browser

and submits this to a .asp file on the server (note that you need a .asp file on the server)

.asp file contains both HTML and scripts/components

Scripts/components invoked and produce new HTML code

resulting page: original HTML + new HTML (generated by asp) - this is sent to client.


Using ASP Server evaluates tag starting with <% and

ending with %> Scripts/components contained within tags Web servers supporting ASP:

– Personal Web Server (Windows 95, 98, NT)– Internet Information Services (Windows NT

Server, 2000 Server, Server 2003, XP)


ASP Application Dell Computers

– http://www.dell.com Barnes and Noble Book Store

– http://www.bn.com Pricescan

– http://www.pricescan.com


ASP Basics

ASP file is a text file with the extension .asp

it contains any combination of:– Text– HTML Tags– ASP Script Commands/Components


ASP Script ASP Script could be VBScript or Jscript

(ECMAScript) A script is a series of commands or

instructions. Script command instructs the web server

to perform an action. VBScript is similar to Visual Basic and

Visual Basic for Application (VBA).


VBScript Basics Not case sensitive Declaring Variables

VBScript does not require variable declarations, but it is good scripting practice to declare all variables before using them. To declare a variable in VBScript, use the Dim, Public, or Private statement.


Declaring VariablesDim: Declares variables and allocates storage space. Variables

declared with Dim at the script level are available to all procedures within the script. At the procedure level, variables are available only within the procedure. Ex. Dim A,B

Private: Used at script level to declare private variables and allocate storage space. Private variables are available only to the script in which they are declared

Public: Used at script level to declare public variables and allocate storage space. Variables declared using the Public statement are available to all procedures in all scripts in all projects.


VBScript Basics

VBScript Operators:– Arithmetic: +, -, *, /, ^– Comparison: =, <>, <, >, <=, >=– Logical (for Boolean variables): Not, And,

Or, Xor


VBScript Basics

Conditional Statement:– IF … Then… Else

• If condition Then [Statement]• elseif condition-n Then [elseifstatment]…• else [elsestatements]• End if


VBScript Basics Loop:

– Do … Loop– While …Wend– For … Next– For Each …Next

Procedures:– Sub– Function


ASP Demo ASP uses <% and %> to enclose script commands.

<html><head><title>ASP Example 1</title></head><body> <p>This page was last refreshed on <%= Date %> </p> <p>Now it is <%= Now %> </p></body></html>

Note 1: The VBScript function Now returns the current time, Date returns current date.

Note 2: No data is input by the user


Running ASP

Save file with .asp extension on server Client accesses the file in similar

fashion to .htm (or .html) file Server detects .asp extension and runs

script within ASP tags Results sent to clienthttp://128.255.21.191/Example1/Example1.asp


Client-Server Structure

IIS

Client

request

Running ASPScript...

results


Example 2 <html> <head><title>ASP Example 2</title></head> <body> <form method="POST" action="resultofexample2.asp"><p>A= <input type="text" name="ValueofA" size="20"></p><p>B= <input type="text" name="ValueofB" size="20"></p><p><input type="submit" value="Calculate" name="B1"></p></form></body></html>

http://128.255.21.191/Example2/Example2.htm


Example 2 see web siteContained in HTML code:

<%@ language="vbscript" %>

<% dim A, B

A=Request.form("ValueofA")

B=Request.form("ValueofB")

%>

……….

<p>A+B= <%= eval(A)+eval(B) %> </p>

<p>A-B= <%= eval(A)-eval(B) %> </p>

<p>A*B= <%= eval(A)*eval(B) %> </p>

…….


example 2 asp

<html> <head><title>Example 2 ASP Page</title></head> <body> <p>Example Page <%@ language="vbscript" %> <% dim A, BA=Request.form("ValueofA")B=Request.form("ValueofB") %> </p> <p>A+B= <%= eval(A)+eval(B) %> </p> <p>A-B= <%= eval(A)-eval(B) %> </p> <p>A*B= <%= eval(A)*eval(B) %> </p></body></html>


Database Overview


What is a Database? A database is an organized collection of

related data, typically stored on disk, and accessible by possibly many concurrent users.

Most common is relational database, which is a tabular database in which the data is defined so that it can reorganized and accessed in a number of different ways


Database Management Systems DBMS A program to access, manipulate and present

the data to a user. Example DBMS:

– Oracle– Sybase (Microsoft SQL)– IBM’s DB2, IMS and SQL/DS– dBase– Access


Relational Database Structure

set of tables containing data fitted into predefined categories.

each table(relation) contains one or more data categories in columns.

each row contains a unique instance of data for the categories defined by column.


Example: Access

Relational database Fairly good GUI. Can use SQL


Relationships in Access

Multiple tables in one database Matching key fields between table

– A key is usually a field with the same name in both tables.

– Such key is primary key for one table, foreign key in the other table.


SQL SQL: Structured Query Language It is used to query from and update

database. Systems using SQL:

• Oracle• Sybase• Microsoft SQL server• Access


SQL

Standard SQL commands:– Select– Insert– Update– Delete – Create


SQL Exampledatabase - example3.mdbtablename - table1columnname - ID, ItemName, Price


SQL Example To find out the ‘Price’ when ‘ItemName’

equals to Candy

SELECT Price FROM Table1 WHERE ItemName = ‘Candy’

Note:

Can SELECT * to return whole row as an object - see Example 3 on website


SQL Basic

Insert tablename (fieldname1, fieldname2…)

values (value1, value2)

update tablename

set column_name1=expression1


SQL Basic

Create tablename (fieldname1 type, fieldname2 type)

Delete [*] from tablename where clause (deletes whole row)


Database Integration Requirements

Server (IIS) Database

• Internet database connector (ODBC) not always required can use ADODB

Dynamic Web Page (asp)• User Input using HTML forms• Data Transmission• Retrieving data from database• Display results


Operation

database

Server

Client

HTML

ASP


Using web browser to access a database Web pages and forms are used to

provide access to the database. Database can be queried or updated. Platform-independent front-end. Database vendor-independent front-end Client machine does not need database

networking software


Example Implementation

Step 1: HTML file (containing forms) for user input on server.

Step 2: Database on server Step 3: Setup database connection

(ODBC)


Step I: HTML File with Forms Example:<form method="Post" action="Find.asp">

<p> <select name = "item" method ="post" size ="1"><option selected value="Gum">Gum</option><option selected value="Suckers">Suckers</option><option selected value="Taffy">Taffy</option><option selected value="Skittles">Skittles</option><option selected value="M&Ms">M&Ms</option><option selected value="Lifesavers">Lifesavers</option><option selected value="Snickers">Snickers</option></select><input type="submit" value="Tell me the price"></p></form>

This captures user input and sends result to result.asp


HTML Forms Examplehttp://128.255.21.191/Example3/Example3.htm


Step II: Database

Under the home directory, create the access database named “Candy.mdb”

tablename - Products columnname - ID, ItemName, Price


<%@ LANGUAGE='VBSCRIPT'%><html><head></head><body><%dim priceSet MyConn = Server.CreateObject("ADODB.Connection")set rs = Server.CreateObject("ADODB.Recordset")MyConn.Open "DRIVER={Microsoft Access Driver (*.mdb)}; DBQ=" & Server.MapPath("Candy.mdb")item = Request.form("item")Set RS = MyConn.execute("Select * from Products where Candy = '" & item & "'")

if rs.Eof thenPrice = ""elsePrice = RS("Price")End ifResponse.Write("It will cost you $" & price)

Set MyConn = nothingSet rs = nothing

%></body></html>


Running ASP

Check the extension (asp) server evaluates tag starting with <%

and ending with %> server replaces the tags with normal

HTML using scripts results page: original Markup + new

Markup(generated by asp)


Result


Java2 Enterprise Edition

EJBs (Enterprise JavaBeans) ----picture PCWeek

Server Side Programming ASP1 Server Side Programming Database Integration Peter O’Grady.

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Transcript of Server Side Programming ASP1 Server Side Programming Database Integration Peter O’Grady.