One area where XML is anticipated to be particularly important is in area of electronic commerce.

Traditional mechanisms for electronic data interchange (EDI) are based on interchange of messages between computer systems of two or more businesses. Each message has to be decoded before its contents can be processed or presented to users. Web-based commerce has, by contrast, been based on concept of completing an HTML form and then posting results back to server for processing, without any details of transaction being retained by party completing form.

XML-coded files are, by their nature, ideal for storing in databases. Because XML files are both object-orientated and hierarchical in nature they can be adapted to virtually any type of database, though care sometimes needs to be taken to ensure that enough structural data is retained in database to reconstruct original file.

Data stored using non-XML notations will need appropriate application software to process it, but XML-coded file will correctly identify where each piece of such data belongs in completed document and where it has been stored prior to use.

By storing data in clearly defined format provided by XML you can ensure that your data will be transferable to a wide range of hardware and software environments. New techniques in programming and processing data will not affect logical structure of your document's message. If more detail needs to be added to file all you need to do is to update model and then add new markup tags where required in document instance. If a completely new style is required then existing document model can be linked to new one to provide automatic updating of document structures.

The following entities are predefined in XML:

Entity References Character

< means "less than - < " > means "greater then - > " & means "ampersand - & " " means "quotes - " " &apos means "apostrophe - ' "

Since, right now we do not plan to go very deep into XML coding, we'll leave data definition here, and move future implication of XML.

Extensible Markup Language (XML), which complements HTML, promises to increase benefits that can be derived from wealth of information found today on IP networks around world. This is because XML provides a uniform method for describing and exchanging structured data. The ability to describe structured data in an open text-based format and deliver this data using standard HTTP protocol is significant for two reasons. XML will facilitate more precise declarations of content and more meaningful search results across multiple platforms. And once data is located it will enable a new generation of viewing and manipulating data.

Consider an industry where interchange of data is vital, such as banking. Banks use proprietary systems to track transactions internally, but if they use a common XML format over Web, then they'd be able to describe transaction information to another institution or an application (like Quicken or MS Money). Of course, they'd also be able to present data in a pretty Web page. FYI: This markup does exist. It's called OFEX, Open Financial Exchange format.

Under certain circumstances, if IE 4 on PC comes across a tag with proper contents, a function is started that gives a user opportunity to update installed software. If you're using Windows 98, it's possible that you've seen this process in action without knowing it was an XML application.