Collaborations‎ > ‎

ECommerce Lecture

ECommerce Lecture

Ecommerce, Web Services and XML


July, 2002

A Web Robot - service available since 1994.

A series of lectures presented in July 2002 for the subject - Comp3410 Information Technology in Electronic Commerce at the Department of Computer Science, Australian National University.

The lecture series provides an introduction to XML, DTD's, schemas and XSL transformations presented in the context of web services. Two web services featured are an online robot and infrastructure for supporting Supervisory Control and Data Acquisition (SCADA) with thin clients utilising the GSM phone network for communication.

Also discussed are SMS messaging on mobile phones and some aspects of human behaviour important to the commercial success of web services, in particular the significance of Zipfs distribution.

Links to other eCommerce Lectures pages

XML

XML - eXtensible Markup Language

Ken Taylor - incorporating course notes by Ramesh Sankaranarayana July 2001

     A language for creating other markup languages...

Xml defines content and not presentation.

  • Derived from SGML.
  • Create your own tags.
  • Well defined structure.
  • XML is strict about syntax.
  • Unlike HTML errors in XML syntax halt document processing, and users or applications receive error messages, not a best-guess interpretation of the document structure.
  • This removes ambiguity.
  • XML can be used to create markup languages like HTML.

XML vs HTML

Ken Taylor based on course notes by Ramesh Sankaranarayana July 2001

      HTML defines format...

Look at the following HTML example.

<html>
<body>
<H2>John Doe</H2>
<P>2 Backroads Lane<br>
Timbuctoo<br>
045935435<br>
John.Doe@Timbuctoo.com<br>
</P>
</body>
</html>

  • Note: This is not valid XML as its not well formed.
  • Well formed HTML is called XHTML.

This will display as:

John Doe

2 Backroads Lane
Timbuctoo
045935435
John.Doe@Timbuctoo.com

What we are specifying here is how the document is to be rendered, and not what information is contained in the document.

While a human could read this and gather information about the embedded data, a machine could not. Humans can assist machines to obtain information from such pages by a technique known as page scraping. An example is Betman which interacts with the NSW TAB site.

Decoupled content

Ken Taylor based on course notes by Ramesh Sankaranarayana July 2001

     XML defines content...

Now look at the following XML example.

<contact>
<name>John Doe</name>
<address>2 Backroads Lane</address>
<country>Timbuctoo</country>
<phone>045935435</phone>
<email>John.Doe@Timbuctoo.com</email>
</contact>

<contact>
<name>John Doe</name>
<address>2 Backroads Lane</address>
<country>Timbuctoo</country>
<phone>045935435</phone>
<email>John.Doe@Timbuctoo.com</email>
</contact>
Comments