XML Tags Overview
XML provides a means of including metadata (the XML tag) in the document. This metadata describes the meaning or function of another piece of data in the document. For example, a defendant's name might appear in an XML document as
<DefendantName>John Doe</DefendantName>
The XML tag makes it easier for another application to correctly interpret the meaning of the data in the document. The application can more easily differentiate between the defendant, plaintiff, or author. When the sending and receiving applications agree on a common set of tags to describe the data in the document, the XML tag allows the receiving application to read, extract, and manipulate the data without ambiguity. This set of tags—the ground rules for the electronic transaction—is specified in a Document Type Definition (DTD) or in a more recent format, an XML Schema.
XML in and of itself offers some utility, but there are a host of other technologies and tools that have grown up around XML. Coupled with these technologies and tools, XML is a breakthrough technology. Some of these technologies and tools include:
- Programmatic tools to read XML (parsers) and identify data by tag name or location within the document hierarchy. There are standalone parsers and parsers built into Web browsers.
- Extensible Stylesheet Language Transform (XSLT), which allows one application to extract data from one document and completely transform it into another document with the same or different meaning. The power of XSLT goes far beyond Cascading Style Sheets (CSS) in that the transformed document may differ from the original document in meaning, not just format.
- XML Path Language (XPATH), to more easily identify parts of an XML document and to better deal with data types such as strings, numbers, and Booleans (true or false values).
