Bogdan Blaszczak

There is no doubt that the World Wide Web Consortium (W3C) XML Schemas enjoy quite a success. They are used in many major software environments and are applied to many domains, from finance to the Search for Extra Terrestrial Intelligence (SETI). But what if, despite all of that, the standard schema facilities aren't enough to solve your problems? Fortunately, the W3C working group left the door open for schema extensions. You can use elements to add your own information to a schema. Also, all schema elements allow additional attributes qualified with a namespace other than the XML Schema namespace itself. Listing 1 shows a sample schema with an annotation. An annotation can be the first child of any other schema element (see www.w3.org/TR/xmlschema-1). An can have any number of or children. The el... (more)