RE: W3C acknowledges RDQL submission from HP

How does RDQL handle reified properties?  Nested sub-queries?

All the best, Ashok 

________________________________

From: www-rdf-interest-request@w3.org
[mailto:www-rdf-interest-request@w3.org] On Behalf Of Bob MacGregor
Sent: Friday, January 16, 2004 9:06 AM
To: www-rdf-rules@w3.org; www-rdf-interest@w3.org; www-rdf-rules@w3.org
Cc: andy.seaborne@hp.com; eric@w3.org; em@w3.org
Subject: Re: W3C acknowledges RDQL submission from HP

 

RDQL is a good thing.  It provides a platform for experimentation
for constructs (e.g., USING) that aren't in SQL.  I imagine that 
optional clauses may also find theirway into RDQL.  However, it
appears that basic constructs like OR and NOT are missing from
the language. 

Note: Adding 'NOT' is not without controversy, since the deductive
DB folks will want it to mean negation as failure, while the open world
folks will want it to mean classical negation.

In my opinion, it would be a mistake to consider
standardization of a language that leaves out some very basic 
(and essential) capabilities.
Therefore, I would recommend reducing the hype a bit (the
word 'standardization') until the language begins to mature.

Cheers, Bob

At 10:45 AM 1/15/2004, Dan Brickley wrote:




Hi all. I'm crossposting this to the general Interest Group list and 
the 'rules and query' list, www-rdf-rules. I've set reply-to: to the
latter. See http://lists.w3.org/Archives/Public/www-rdf-interest/
and http://lists.w3.org/Archives/Public/www-rdf-rules/ for archives of
both. EricP's post at 
http://lists.w3.org/Archives/Public/www-rdf-rules/2001Sep/0000.html has 
more info about origins of the www-rdf-rules list, including info on 
(un-)subscribing.

Anyway, I wanted to let folks on both lists know that W3C published a 
W3C Member note on RDQL, "A Query Language for RDF" last week. 

The document itself is at:
http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/

Info on the submission is at: http://www.w3.org/Submission/2003/06/

...and our 'team comment' on the doc is at:
http://www.w3.org/Submission/2003/06/Comment

As we say in the comment, "The RDQL submission is particularly welcome 
[...] as it provides a 'strawman' target for discussion,
testing, evaluation against use cases and consideration for possible
standardization. [...]  Information from application developers who 
have worked with RDQL-based query engines will be of particular use in
understanding the design tradeoffs in this area.".

I know that many folks on the RDF IG lists have built or used RDF query 
systems which use either RDQL or a very similar approach (RDFdb, Squish,

etc etc.). Discussion on the utility and limits of such languages is 
(as always) very welcome on www-rdf-rules. I'm particularly interested
to see case studies of real world apps that have been coded against such

an interface, and to learn more about problems (and successes!) that 
you've encountered while building such systems.

Followups to mailto:www-rdf-rules@w3.org please,

cheers,

Dan

=====================================
Robert MacGregor
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macgregor@isi.edu 
Phone: 310/448-8423, Fax:  310/822-6592
Mobile: 310/251-8488

USC Information Sciences Institute 
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