Lecture 6 Data Driven Design

Lecture 6 Data Driven Design - Presentation Transcript

SFDV2001 – Web Development Lecture 6: Data Driven Design

Server

What is a server

A machine that “serves“ files

How to get a file

you connect to the computer

send it a message saying what file you want

it sends that file to your machine

Must have

A program that listens for requests and sends files when asked. This is what makes it a server.

Two main ones Apache (67%), MS IIS (21%)

11/09/07 (SFDV2001:24)Data Driven Design

Client

Definition

A machine that makes requests of a server and then displays the results.

Program that are web clients are

IE, Mozilla, Netscape, Safari

You request a file

a get message is sent and the page is returned

Special case http://www.otago.ac.nz is interpreted as www.otago.ac.nz/index.html

11/09/07 (SFDV2001:24)Data Driven Design Download cycle

Problem

not customized to the individual,

manual updating of information

no memory of previous visits

Client Server get index.html <html><head><title>Index</title><body> This is a test page</body></head>

Dynamic content

We can have changing content

Latest news stories

Games

Latest product information

Two type

Server-side

Client-side

Server-side 11/09/07 (SFDV2001:24)Data Driven Design

Types

ASP, PHP, CGI, SSI

you will see <name>.php e.g. cosc360.otago.ac.nz/index.php

Cycle

client request

server processes request and gathers information

returns contructed page that is HTML

client displays recieved page

Server-side 11/09/07 (SFDV2001:24)Data Driven Design

Advantages

Up-to-date information

easier to maintain and update

client machines just see HTML

removes redundant information storage

Disadvantages

Server has to do more work

opens up security issues

people may not be able to get the same page later

Client-side 11/09/07 (SFDV2001:24)Data Driven Design

Types

Javascript, Java, imagemaps

content sent to your machine and it calculates what to do.

Advantages

Users machines does work instead of server

Disadvantages

Sending more data

everybody can see how your site works

Dependent on the client browser support

Data driven design

Static html and CSS is not good enough.

We have lots of data and the web should be just one way of viewing that data.

Need to be

Dynamic

User centred

Accessing single data source

Maintainable

Current

There must be a better way!

LAMP

L inux, A pache, M ySQL, P HP/Perl/Python

Linux Operating system

Apache Web server

MySQL Database

PHP Programming language

These create a free dynamic content web server

Underlying concepts similar between all database programs

Dynamic content the key

Database

Database

One or more Data file.

Data file

File containing rows of data.

Principles

Information should occur only once in an organisation

Postal address – Library, department, registry, OUSA, clubs and socs, careers advisory service, ...

Accessing information should be fast

Fast ways to search 30,000 records.

Example Database

Student records database.

StudentID, Fname, Sname, DOB, Addr

StudentID, PaperCode, Fees, Mark

PaperCode, Name, Desc, Year, Department

11/09/07 (SFDV2001:24)Data Driven Design StudentID Fname Sname DOB 933333 Simon Smith 18/12/80 7456324 Jane Jones 10/01/83 8756432 Ann Archer 31/03/84 . . . . . StudentID PaperCode Fees 933333 COMP112_S1_04 Enrld 933333 ENGL127_S2_04 Unproc 7456324 COMP102_S1_04 Enrld 8756432 COMP102_S1_04 Enrld 8756432 COMP112_S1_04 Enrld 8756432 ENGL127_S2_04 Unpro . . . PaperCode Name Year COMP102_S1_04 Infoma.. 2004 COMP112_S1_04 Comput.. 2004 ENGL127_S2_04 Comput.. 2004 . . . . . Enroll Student Papers

Example Database

Your name and address is stored in one place.

You are referred to by your StudentID everywhere else.

Your enrolment in your course is a row in a datafile.

9334567 COMP112_S2_2005 Enrolled ???

The University has a massive database with many links

Lecturers, courses, labs, lecture theatres, examinations, departments, divisions

Alumnia Database

National Student Number, graduates surveys

Query

To extract information you query the database.

Query:

I want a list of the names of people enrolled in the course.

Process:

Find all the people enrolled in the course and then match their ID numbers to the IDs in the Student file. Extract all the names for students with matching IDs.

MYSQL:

SELECT s.name FROM enrollments e, student s WHERE e.papercode LIKE 'COMP112_S2_2005%' AND s.id = e.StudentID;

Views of Data

Businesses store information in databases

Views of data

Managers like to look at reports.

Sales staff want to know what is in stock and the current price.

Clients want to know about products and descriptions.

Accountants want stock and sale information.

etc.......

These are all accessing the same data

Wouldn't it be nice to have the web site accessing the same information.

Customisation

Case study – Blackboard & PIMS.

Login to personal information.

Access information about courses.

Discussion boards with updatable content.

Need more than just HTML to do all that.

Server needs to extract information from a database

Present it in an acceptable form.

Discussion Board

Many people accessing and adding content.

Need to have web based access so users can

Add content.

View new messages.

Select a thread.

Reply to messages.

Has to be dynamic, rather than static.

Weblog – blogs also need these properties.

Wiki – lots of visitor content alteration.

MySQL

MySQL

Free implementation of SQL (Structured Query Language).

Database management software.

Allows full database control and programming.

Very common in conjunction with PhP as they are both free and run on Linux and play nicely with Apache.

Relational Database

Complex once you are designing them for optimal use

ASP, PHP & JSP

A ctive S erver P age. (MS) ‏

P HP H ypertext P reprocessor. (IBM) ‏

J ava S erver P ages (Sun) ‏

These systems allow

Dynamic content.

Full programming language support.

Access to database information

MSaccess.

MySQL.

Oracle etc.

Easier to maintain as many tasks are automated.

Dynamic Navigation

You can use PHP or ASP to add content.

Using the GET part of the URL.

www.games.ac.nz/index.php?show=research

will include the file in directory “inc/” called “research.php”

11/09/07 (SFDV2001:24)Data Driven Design <div id="bodybox"> <? $content = "inc/intro.php" ; if (isset($_GET["show"])) { $content = "inc/" .$ _GET["show"]. ".php" ; } include($content); $modTime = filemtime($content); ?> </div> content = “inc/research.php” content = “inc/intro.php”

Interactive Content