Transcript ASP

Server Side Programming
Database Integration
Peter O’Grady
Server Side Programming ASP
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Content
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Introduction
Server Side Programming (ASP)
Database
Integration
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Introduction
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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
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Data can be kept on servers distributed
across network and accessed via client
(topic of this portion of course)
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Why use Internet to access data?
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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
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How can database be accessed by
web browser?
Server Side Programming
e.g. Microsoft IIS server :
ASP (VBScript, JScript, SQL)
Database
Internet
Web browser
Web browser
Web browser
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Client Side Scripts
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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.
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Server Side Programming (ASP)
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Content
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Server Side programming overview
Example
– Microsoft Internet Information Services (IIS)
– Active Server Page(ASP)
– VBScript/JScript
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Common Gateway Interface
(CGI)
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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.
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IIS
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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
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What is ASP?
Runs on IIS
"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
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What are Active Server Pages?
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Server-side environment
Can provide compile-free application
environment
Combine HTML, scripts, COM and
ActiveX server components.
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Using ASP
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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.
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Using ASP
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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)
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ASP Application
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Dell Computers
– http://www.dell.com
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Barnes and Noble Book Store
– http://www.bn.com
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Pricescan
– http://www.pricescan.com
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ASP Basics
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ASP file is a text file with the extension
.asp
it contains any combination of:
– Text
– HTML Tags
– ASP Script Commands/Components
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ASP Script
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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).
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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.
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Declaring Variables
Dim: 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.
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VBScript Basics
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VBScript Operators:
– Arithmetic: +, -, *, /, ^
– Comparison: =, <>, <, >, <=, >=
– Logical (for Boolean variables): Not, And,
Or, Xor
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VBScript Basics
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Conditional Statement:
– IF … Then… Else
• If condition Then [Statement]
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elseif condition-n Then [elseifstatment]…
• else [elsestatements]
• End if
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VBScript Basics
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Loop:
– Do … Loop
– While …Wend
– For … Next
– For Each …Next
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Procedures:
– Sub
– Function
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ASP Demo
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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
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Running ASP
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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 client
http://128.255.21.191/Example1/Example1.asp
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Client-Server Structure
Running ASP
Script...
IIS
request
results
Client
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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
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Example 2 see web site
Contained 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>
…….
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example 2 asp
<html>
<head>
<title>Example 2 ASP Page</title>
</head>
<body>
<p>Example Page <%@ language="vbscript" %>
<% dim A, B
A=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>
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Database Overview
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What is a Database?
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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
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Database Management Systems
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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
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Relational Database Structure
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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.
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Example: Access
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Relational database
Fairly good GUI.
Can use SQL
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Relationships in Access
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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.
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SQL
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SQL: Structured Query Language
It is used to query from and update
database.
Systems using SQL:
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Oracle
Sybase
Microsoft SQL server
Access
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SQL
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Standard SQL commands:
– Select
– Insert
– Update
– Delete
– Create
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SQL Example
database - example3.mdb
tablename - table1
columnname - ID, ItemName, Price
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SQL Example
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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
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SQL Basic
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Insert tablename (fieldname1,
fieldname2…)
values (value1, value2)
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update tablename
set column_name1=expression1
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SQL Basic
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Create tablename (fieldname1 type,
fieldname2 type)
Delete [*] from tablename where clause
(deletes whole row)
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Database Integration Requirements
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Server (IIS)
Database
• Internet database connector (ODBC) not
always required can use ADODB
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Dynamic Web Page (asp)
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User Input using HTML forms
Data Transmission
Retrieving data from database
Display results
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Operation
ASP
database
Server
HTML
Client
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Using web browser to access a
database
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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
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Example Implementation
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Step 1: HTML file (containing forms) for
user input on server.
Step 2: Database on server
Step 3: Setup database connection
(ODBC)
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Step I: HTML File with Forms
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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
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HTML Forms Example
http://128.255.21.191/Example3/Example3.htm
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Step II: Database
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Under the home directory, create the
access database named “Candy.mdb”
tablename - Products
columnname - ID, ItemName, Price
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<%@ LANGUAGE='VBSCRIPT'%>
<html>
<head>
</head>
<body>
<%
dim price
Set 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 then
Price = ""
else
Price = RS("Price")
End if
Response.Write("It will cost you $" & price)
Set MyConn = nothing
Set rs = nothing
%>
</body>
</html>
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Running ASP
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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)
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Result
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Java2 Enterprise Edition
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EJBs (Enterprise JavaBeans) ----picture PCWeek
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