Why XML

[JamesBowtell]

I'm interested in learning XML as many of my friends who are software developers have activley adopted the use of XML. Why is XML so important to todays and future web based applications?

need some encouragement

Cheers

[penagate]

Dyamic self-descriptive structure, so if some thought is used it can be made forwards and backwards compatible. Also very generic, so adaptable to many situations.

[JamesBowtell]

i understand XML describes the data, does this mean its useful way of creating applications that may interoperate with one another by using XML to describe the information being passed?

[penagate]

The self-descriptive part is of utmost importance when you can have a document of variable structure.

Consider a typical byte structure as used in OS API's and applications worldwide.

struct ABC
{
  int a;
  int b;
  char c;
}

When that is sent over a communication channel, the recipient will receive 9 bytes of data. This could mean anything. While it's very efficient, it will only produce the correct result if the structure is known beforehand.

Now consider this:

<abc>
  <a>...</a>
  <b>...</b>
  <c>...</c>
</abc>

One can easily tell what is a, b, and c, as the structure is inherently part of the document itself.

This can be useful for inter-application communication as the document type can be inferred from the document structure. Whether or not this is useful depends on how the applications are engineered, but if an application is built to take advantage of XML it does make it much more versatile as opposed to static structures as used in the first example. This is very useful with web services which can return variable types and amounts of data, and tied in with databases. A database access service which returns a resultset in XML can handle any query processed through it.

Does that help?

[NOTSOSURE]

Here are some reasons why some people and myself are attracted to XML


You can create your own TAGS

Rather than wait for standard bodies to adopt TAG set enhancements, or browser companies to adopt each others standards, with XML you can create your own set of TAGS at your own pace

Develop tools that meet your exact needs

By defining your own TAGS, you create the mark-up language in terms of your specific problem set!

Rather than relying on a generic set of TAGS which suit everyone’s needs adequately, XML allows every person/organisation to build their own library which suits their needs perfectly.

XML allows each specific industry to develop its own TAG sets to meet its unique needs.