• 
  
  Presentation Oriented Publishing (POP) – the same data in a web browser, mobile phone and a PDA. 
  
  


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  Message Oriented Middleware (MOM) – B2B. 
  
  

This is where an application uses XML as a message format for communication between different systems. 

• 
  
  XML used for exchanging database contents. 
  
  

To illustrate the applications we will use an example of an online shopping system.

1) The owner of the online shop wants to provide an online service so that it also works on mobile phones and PDAs.

Data in the store database is used to generate a XML document. This same XML document can be transformed using XSL (covered in a later section) into HTML, WML or any other format. This would allow the information to be displayed on mobile phones and PDA.

2) The owner wants to automate order processing and fulfilment.

Since the 1970s, systems have used Electronic Data Interchange for computer-to-computer communication. This allowed orders and invoices to be sent using a messaging standard. The problem with EDI is that it is very expensive to buy and EDI system, therefore only large companies would use it.

Two companies agreeing on a DTD can send messages over the Internet using XML. Problems occur regarding security and reliability but these are being addressed.

Going back to our example, when a customer orders a product from the online shop, the shop sends a standard message to the delivery agent. The delivery computer system automatically updates itself with the latest orders and automatically sends an acknowledgement back to the shop.

Messages could also be sent from the suppliers to the online shop to update the inventory on the specific products.

3) The marketing department would like to extract the data from the online shop so they can organise product promotions and sales.


However, the marketing database is in MS Access and the shop uses Oracle. There is no specific standard for exchanging data from one database to another.

XML allows all the tables to be totally described by using custom tags.

<table>

<field>

etc.