Exercises Topic5: eXtensible Mark-up Language

Topic5: eXtensible Mark-up Language

XML (Extensible Markup Language) is a set of rules for encoding documents electronically. It is markup language like HTML. It was mainly design to carry the data. The tags of XML are not be defined. You have to define by own.

Difference between XML and HTML

• XML was designed to transport and store data, with focus on what data is.

· HTML was designed to display data, with focus on how data looks.

Attributes

· Provide extra information about elements.

· Placed inside the starting tag of an element.

· Always come in name/value pairs.

· Example dog ID attribute

GrisWald

Entities

The following entities are predefined in XML:

Entity Character

< <

> >

& &

" “

HTML



HTML, which stands for HyperText Markup Language, is the predominant markup language for web pages.



Basic Format

Now we are able to start learning about HTML tags. An HTML tag will always begin with a "less than" sign, like this: <. The tags will end with a "greater than" sign, like this: >. An example would be the tag used to underline text, <u>. You would place this before the text you want to underline. This is called an opening tag, which begins the operation you wish to perform. In order to end the underlining, you must use a closing tag. A closing tag will be the same as the opening tag, but will have a forward slash before the command, like this: </u>. So, if you would like to underline the phrase "HTML Rules!", you would write the following in your text editor:

<u>HTML Rules!</u>

The result of this would be:

HTML Rules!

Reference

Ince, D. (2004). Developing distributed and e-commerce applications (2nd ed.). Harlow,Essex, UK: Addison-Wesley.

Exercises Topic4: Common Gateway Interface

Topic 4: Common Gateway Interface

Common Gateway Interface

It is standards for the creation of dynamic HTML documents with the use of external small programs. To run the programmed CGI needs interpreter or compiler. It can also be used for secure website for transaction process like ordering some gift for your friends.

Common Gateway Interface Demonstration

1. Flat file system

Usually the python CGI Script runs at the Flat file system

2. Environment Variation

Exercise has been display at ZOPE using the local python script.

Reference  

Ince, D. (2004). Developing distributed and e-commerce applications (2nd ed.). Harlow,Essex, UK: Addison-Wesley.

Exercises Topic3: Database Server

Topic3: Databases Server

Type of Databases

1. Flatefile

· It is just a text file

· suits applications that want the database to function like a rolodex

2. Relational DBMS

· It has advantages of “one to many” between two tables

· Communication data sources uses ODBMS/SQL

3. Object-oriented OODBMS

· Object oriented model has data objects which are encapsulated by classes that have predefined characteristics

· Data are accessible only through messages which they recognize

· ZOPE uses an OODBMS inside its core

Two and Three tier databases

2-tier Databases model: data tightly bound with stand alone application.

3-tire Databases: more popular for business. It mainly used for Database backend is an ERD (Enterprise Relational Database) such as Sybase or Oracle.

Advantages:

1. Load distribution

2. Transparency

3. The ease of building custom application

4. Security controlled at the middleware layer

Disadvantages


1. Increased rolling resistance


2. Less control and traction at higher speeds


3. developing a host application is take long time


Reference

Ince, D. (2004). Developing distributed and e-commerce applications (2nd ed.). Harlow,Essex, UK: Addison-Wesley.

Exercises Topic2: Clients, servers and distributed paradigms

Topic2: Clients, servers and distributed paradigms

Client-Server Computing

The term client-server describes the relationship between two software applications which client send request from the server. The server provides specialist service to the client. This service can be applied to two programmes running on a single computer. The most common is computer transaction using client-server. For example, “to check your bank account from your computer, a client program in your computer forwards your request to a server program at the bank” (SerchNetworking.com, 2010). There are various types of client-server exists such as File server, Database server, Transaction server, Groupware server (IBM Lotus Notes), Object servers (ORB-communicating object), Web application server (HTML,JAVA). The figure shows the different client-server systems just shuffle the location of application logic around from the client end to the server end of the network relationship. The client-server development projects are connected to E-Commerce and M-commerce system.

Distributed Computing

A distributed computer system consists of multiple software components on multiple computers running as a single system. The computers in a distributed system can be physically close together and connected by a local network, or they can be geographically distant and connected by a wide area network. A distributed system can comprise any number of possible configurations--mainframes, personal computers, workstations, minicomputers, and so forth. The goal of distributed computing is to make such a network act as a single computer.

In short, client/server computing provides a mechanism for disparate computers to cooperate on a single computing task. Distributed computing also refers to the use of distributed systems to solve computational problems. In distributed computing, a problem is divided into many tasks, each of which is solved by one computer.

Reference

SerchNetworking.com (2010). Client/Server. Retrieved on 13th April 2010 from

http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci211796,00.html

Exercises Topic1: E-commerce, distributed applications

Topic1: E-commerce, distributed applications

Ecommerce

The Buying and selling of goods and services on the internet is called e-commerce. It includes B2B buying and selling, the security of business transactions, the B2B exchange of data, the gathering and use of demographic data though Web contacts.

Why E-commerce is Important

· It is user friendly

· Open 24*7 hr

· Globalization- u can buy anywhere in any country

· It is much chipper then in the shop

· It provides flexibility, speed, competitive

On the other hand there are some issues regarding internet security and some people are not relay on the internet shopping because they think that its breach of privacy.

There are some sites with e-commerce like

· Greengrocer store in Melbourne and Sydney: http://www.greengrocer.com.au/

· Travel agent: http://www.travel.com.au

· Gift shop: http://www.wishlist.com.au/

· Wine store: http://www.wineplanet.com.au/

E-commerce Infrastructure

Distributed Application

Computing is said to be "distributed" when the computer programming and data that computers work on are spread out over more than one computer, usually over a network. Distributed application have two parts first the 'front end' that requires minimal computer resources and runs on the client computer(s), and (2) the 'back end' that requires large amounts of data crunching power and/or specialized hardware, and runs on a suitably equipped server computer.

Reference

Ince, D. (2004). Developing distributed and e-commerce applications (2nd ed.). Harlow, Essex,UK: Addison-Wesley