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Re: use case dc-02

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Tue, 13 Apr 2004 11:00:03 +0300
Message-Id: <91C790BD-8D20-11D8-8853-000A95EAFCEA@nokia.com>
Cc: "Eric Prud'hommeaux" <eric@w3.org>, Rob Shearer <Rob.Shearer@networkinference.com>, public-rdf-dawg@w3.org, "'Howard Katz'" <howardk@fatdog.com>
To: "ext Dirk Colaert" <Dirk.Colaert@quadrat.be>

This looks like a good use case. A variant that is also often seen
is determining the most "popular" queries, and regularly executing
and caching results for them to improve the responsiveness of the 


On Apr 08, 2004, at 18:06, ext Dirk Colaert wrote:

> Use case dc-02: Query a query
> A server stores all queries committed. From time to time the security
> administrator wants to know who has tried to query on data which 
> he/she had
> no access to.
> -----Original Message-----
> From: Howard Katz [mailto:howardk@fatdog.com]
> Sent: jeudi 8 avril 2004 16:14
> To: Dirk Colaert; Eric Prud'hommeaux
> Cc: Rob Shearer; public-rdf-dawg@w3.org
> Subject: RE: Requirement: queries written as RDF
>>> (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... :-)
> It does sound wonderful, doesn't it? I too would like to know what you 
> would
> want to query in a query. Examples anyone ... ?
>> 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


Patrick Stickler
Nokia, Finland
Received on Tuesday, 13 April 2004 04:26:22 UTC

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