The ID/IDREF mechanism for locating elements in XML documents has been generalized in XSL to the notion of keys.
ID/IDREF is only useful when:
The document has declarations that identify the ID and IDREF attributes and
The processor is capable of processing the declarations
Using select expressions (XPath) to locate elements may be inefficient
Declaring keys gives the stylesheet processor an indication of what elements should be cached for fast access.
Copyright © 1999, 2000 by Arbortext, Inc. (http://www.arbortext.com/), Sun Microsystems, Inc. (http://www.sun.com/)
