XML Features

The following bullets describe XML features:

• Data Exchange, From Structured to Unstructured Data: XML enables a universal standard syntax for exchanging data. XML specifies a rigorous, text-based way to represent the structure inherent in data so that it can be authored and interpreted unambiguously. Its simple, tag-based approach leverages developers' familiarity of HTML but provides a flexible, extensible mechanism that can handle the gamut of "digital assets" from highly structured database records to unstructured documents and everything in between. " W3C

• SGML Was Designed Specifically for Documents - XML is Designed for Potentially Any Data: The SGML markup language was specifically designed for documents. Web-centric XML is like a toolkit that can be used to write other languages. It is not designed for documents only. Any data that can be described in a tree can be programed in XML.

• A Class of Data Objects - A Restricted Form of SGML: www.oasis-open.org describes XML as follows: "... XML, describes a class of data objects called XML documents and partially describes the behavior of computer programs which process them. XML is an application profile or restricted form of SGML, the Standard Generalized Markup Language. By construction, XML documents are conforming SGML documents."

• XML's Many Uses...: A W3C.org press release describes XML as follows: "... XML is primarily intended to meet the requirements of large-scale Web content providers for industry-specific markup, vendor-neutral data exchange, media-independent publishing, one-on-one marketing, workflow management in collaborative authoring environments, and the processing of Web documents by intelligent clients.

• Metadata. XML is also finding use in certain metadata applications.

• Internationalization. "XML is fully internationalized for both European and Asian languages, with all conforming processors required to support the Unicode character set in both its UTF-8 and UTF-16 encodings..." Its primary use is for electronic publishing and data interchange ..."

• Parsed or Unparsed Storage Entities: From the W3C.org XML specification proposal: "... XML documents are made up of storage units called entities, which contain either parsed or unparsed data. Parsed data is made up of characters, some of which form the character data in the document, and some of which form markup. Markup encodes a description of the document's storage layout and logical structure.

• XML Processor Reads XML Documents. "... XML provides a mechanism to impose constraints on the storage layout and logical structure. A software module called an XML processor is used to read XML documents and provide access to their content and structure. It is assumed that an XML processor is doing its work on behalf of another module, called the application...."

• Open Internet Standard. XML is gaining wide industry support from other vendors besides, like IBM, Sun, Microsoft, Netscape, SAP, CISCO and others, as a platform- and application-neutral format for exchanging information.

Although this manual is not intended to expound on XML syntax, a brief overview of some key XML topics is presented here. You can refer to the many excellent resources listed in "Additional XML Resources" for more information on XML syntax.