tailieunhanh - What Is XQueryX?

One of the most recent developments in the work on XQuery is the efforts of the World Wide Web Consortium (W3C) to specify the XQueryX language. This language enables the full rendering of XQuery in Extensible Markup Language (XML) for computer-readable use and ensures its compliance with W3C requirements. XQueryX is not designed for direct human use. | Appendix B What Is XQueryX Introduction One of the most recent developments in the work on XQuery is the efforts of the World Wide Web Consortium W3C to specify the XQueryX language. This language enables the full rendering of XQuery in Extensible Markup Language XML for computer-readable use and ensures its compliance with W3C requirements. XQueryX is not designed for direct human use. XQueryX is in the very early stages of development. This topic is included to alert you to this emerging technology and to show the rapid pace of innovation with XML. Note For more information about XQueryX check the W3C site regularly to monitor the evolution of this probable standard. See the W3C paper XML Syntax for XQuery XQueryX of June 7 2001 at http XML Query. Why is XQueryX needed XQueryX is needed to make the programmatic use of XQuery consistent with other XML languages and techniques. XQuery in the form you have learned it so far does not appear in true XML format. By using XQueryX you can turn an XQuery expression into an XML document. If you can represent an XQuery expression in XML through XQueryX then all other XML techniques for navigation and modification are available to the XML programmer. 2 Appendix B What Is XQueryX Example Consider the following FLWR expression from FOR b IN document book WHERE b publisher New Moon Books and b year 1991 RETURN b title Converting this to XQueryX produces the following XML document q query xmlns q http 2001 06 xqueryx q flwr q forAssignment variable b q step axis SLASHSLASH q function name document q constant datatype CHARSTRING q constant q function q i denti fi er book q identi fi er q step q forAssi gnment q where q function name AND q function name EQUALS q step axis CHILD q vari able b q vari able q i denti fi er publi sher q identifi er q step q constant datatype CHARSTRING New Moon Books q constant q function q function name EQUALS q step axis CHILD q vari able b q .