- From: Dirk Colaert <Dirk.Colaert@quadrat.be>
- Date: Thu, 8 Apr 2004 14:26:34 +0200
- To: 'Howard Katz' <howardk@fatdog.com>, Eric Prud'hommeaux <eric@w3.org>
- Cc: Rob Shearer <Rob.Shearer@networkinference.com>, public-rdf-dawg@w3.org
>(2) If queries are represented in XML they can be treated as data > and you can run XQueries over a collection of XQueries. That's interesting. A Query expressed in RDF could be treated as RDF. It would be easy to do queries about queries. That's an argument for using RDF (or a subset, or a convertible format). All we have to do know is find a use case justifying this requirement... :-) Or do we have a solution without a problem? Dirk -----Original Message----- From: Howard Katz [mailto:howardk@fatdog.com] Sent: mercredi 7 avril 2004 7:08 To: Eric Prud'hommeaux Cc: Rob Shearer; public-rdf-dawg@w3.org Subject: RE: Requirement: queries written as RDF I got several responses back from members of the Query wg on the XQueryX question. I particularly liked this one. I don't know if it'll shed any light on our own issues, but it's delightfully clear and succinct. The author prefers to remain anonymous. In response to a question on why XQueryX: > (1) An XML-based syntax was considered easier for machines to > generate and exchange than a human-oriented syntax that would > require some sophisticated parsing. > (2) If queries are represented in XML they can be treated as data > and you can run XQueries over a collection of XQueries. > (3) Since XML is known to be an answer to all questions, it must be > an answer to the question "What would be a good format for expressing > queries over XML data"? In response to a question on the technical difficulties that arose once the requirement was formulated: > Once the requirement for an XML query syntax was adopted, > arguments immediately broke out over the level of detail at which a query > should be broken down into XML elements. The working group finally settled > on two separate approaches that represent extreme points on the spectrum: > (a) The whole query is wrapped in a <query> element, and otherwise unchanged. > This approach obviously does not take the XML syntax requirement very seriously. > (b) The query is parsed, and each and every node in the parse tree (including individual > operators, function calls, steps in path expressions, etc.) is represented by its own > element, thus making the query incredibly verbose. This format is obviously useless to humans. > At various times and places, people have attempted to define some intermediate point > between these two extremes. These attempts have always ended in rancor and controversy. Finally, in a follow-up clarification: > I believe that the editor of the XQueryX specification is currently pursuing both approaches > (a) minimal expansion and (b) maximal expansion. Both will be defined as valid forms of > XQueryX. Just to close on a personal note, I've always felt that XML is the answer to all questions. I'm now coming to feel increasingly that RDF is even more so! Howard > > On Sun, Apr 04, 2004 at 09:23:14AM -0700, Howard Katz wrote: > > [snip ...] > > > > I certainly agree with the sentiments of the second, "human readable" > > > requirement. Interestingly enough, the third, "XML" requirement > > has been the > > > one that's caused the group the most difficulty to my > > knowledge, and at the > > > moment conformance with this requirement has been downgraded to > > optional. I > > > don't know what the major issues have been, but it might be > > interesting to > > > know, if only for the sake of curiosity. > > > > Can we go beyond the meta-lesson of "that may be hard. it's been hard > > in XQuery" to some of the particular problems that requirement caused > > the XQuery WG? Also, was this requirement born of some compelling use > > cases, or a general notion that it's good practice to express anything > > in XML? > > I wasn't trying to impart a particular lesson. My intention, not knowing > what DAWG members know or don't know about it, was simply to > provide data on > the experience of the Query wg in the event that might prove useful to the > group. In response to your questions, I've asked several members of the wg > about their XQueryX experience. If they see fit to pass that on > to me, I'll > be happy to share it with the group. > > Howard >
Received on Thursday, 8 April 2004 08:19:54 UTC