Writing XML
XML is a text format. This makes it relatively easy to write code to generate or interpret such documents, and in a worst-case scenario it's possible for a skilled person to interpret the data.
Two APIs for interpreting XML code--DOM (Document Object Model) and SAX (Simple API for XML)--exist to save developers from reinventing the wheel. While DOM is the W3C-sanctioned API, SAX is widely used.
The word "simple" should not be taken as an indication that SAX is easier to use: on the contrary, because the API is simpler, it leaves more work for the programmer. SAX's popularity is partly due to the fact that it is more efficient than DOM when the application is concerned with extracting data from an XML document (such as an accounting system receiving an invoice delivered electronically in XML format) rather than manipulating the document (as is the case for an XML editor).
Parsers from Apache (which inherited IBM's parser), Microsoft and Oracle support DOM and SAX. A new version of DOM (DOM Level 3) is expected either late this year or early 2002, and will provide new features such as the ability to test whether two objects contain the same content.
