The W3C specification defines XML as a subset of SGML, so to properly understand XML,
it is useful to take a closer look at SGML first.
SGML stands for Standard Generalized Markup Language, and was developed for large scale
applications, aircraft maintenance or power plant documentation, and intended for to be
maintained over the long term.
The reason why XML seems to be so similar to HTML lies in the fact that HTML is defined
as a subset of SGML. XML is actually a lot more similar to SGML than to HTML, because HTML
is only one specific subset of SGML used to describe web pages.
As XML was created to simplify SGML, it is no wonder that the W3C has now decided to redefine
HTML 4.0 as an XML application, thereby creating XHTML 1.0.
To answer this, let us define what XML is not:
It is not a programming language.
It is not the next generation of HTML.
It is not a database.
It is not specific to any horizontal or vertical market.
It is not the solution to all your problems, but it can be a very powerful tool
in building such a solution.
XML is a clearly defined way to structure, describe, and interchange data.
Data in this context really means every conceivable kind of data! You can use XML
for such diverse things as describing mathematical formulas, chemical compounds,
astronomical information, financial derivatives, architectural blueprints, annotating
Shakespearean plays, collecting Buddhist wisdoms, or voice-processing in telephone systems!
To learn more about XML visit the following links to our online manual:
Here are some other useful links where you can learn more about XML and also find
tutorial material:
http://www.w3schools.com/http://www.xml.com/pub/a/98/10/guide1.html#AEN58http://www.w3.org/XML/1999/XML-in-10-pointshttp://www.xml.com/pub/a/2001/03/21/xmlauthoring.htmlhttp://www.ucc.ie/xml/#FAQ-ACRO
