Using XML

This topic explains what XML is, what extensions and companion standards it uses, and what it can do for you.

XML, like Standard Generalized Markup Language (SGML), is a metalanguage. A metalanguage allows you to define a document markup language and its structure. For example, both XML and Hypertext Markup Language (HTML) are derived from SGML.

You can use XML to create your own markup language that includes a set of rules and tags that describe information suited to your needs, for example, name, title, address, and zip code. You define this markup language in a document type definition (DTD) that functions as the standard way to describe your information. Using XML to share standardized information you are no longer required to write programs to focus on proprietary software or convert and translate different data formats.

You and others can use the DTD to tag information that you can then use in a variety of ways: printed on an address label, business card, or stationary; displayed in a Web page; or sorted in a list of data with similar attributes.

For example, you might want to create an efficient way to share information (for example, purchase orders, shipping acknowledgments, order status, and stock status) with your partners and suppliers. You can use XML to share that information by creating and using XML documents that conform to your DTD, in which you specify the standard for the electronic exchange of information.

Although both XML and HTML use tags to describe content, they are also very different:

• HTML describes how to format information for display and is meant for computer-to-human interaction.
• XML describes what the information is and is meant for computer-to-computer interaction.

• Advantages of XML
  Using XML offers advantages over using HTML to exchange information.
• XML standards and extensions
  Other standards and extensions to XML work together to make your information more portable and useful.
• XML tools for i5/OS
  i5/OS™ integrates XML parsers and an XSL processor for Java™ right into the operating system. Additionally, you can use a wide variety of free and licensed programs to help you use XML.
• XML parser and XSLT processor for Java
  Some IBM^® Toolbox for Java™ packages or functions require that you have an Extensible Markup Language XML parser or Extensible Stylesheet Language Transformations (XSLT) processor in your CLASSPATH environment variable.
• XML for C++ Parser, XSL for C++ Transformer, and XML Interface for RPG and Procedural Languages
  The XML for C++ Parser and the XML Interface for RPG and Procedural Languages (RPG, C, and COBOL) allow you to parse, create, manipulate, and validate XML documents. The XSL for C++ Transformer allows you to transform XML documents to another format.
• Additional XML tools and programs
  You can write your programs to take advantage of XML and its extensions and companion standards.