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Minutes of RDF DAWG telecon 2004-11-02 for review

From: Alberto Reggiori <alberto@asemantics.com>
Date: Tue, 2 Nov 2004 22:53:55 +0100
Message-Id: <B163FE42-2D19-11D9-90D4-0011242E4018@asemantics.com>
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>

Minutes of RDF DAWG telecon 2004-11-02 for review



IRC log:  http://www.w3.org/2004/11/02-dawg-irc

1. Convene, take roll, review record, agenda

Attendees: Howard Katz, Hiroyuki Sato, Andy Seaborne, Alberto Reggiori,  
YoshioFukushige, Simon Raboczi, Dan Connolly, Kendall Clark, Dave  
Beckett, Kevin Wilkinson, Steve Harris, Pat Hayes, Janne Saarela

Regrets: Eric Prud'hommeaux, Farrukh Najmi, Tom Adams, Jos De Roo

Scribe: Alberto Reggiori

The minutes of 2004-10-26 telecon


with amendments



Next meeting: Tuesday 2004-11-09 at 14:30 UTC, Dave Beckett to scribe

The following actions were CONTINUED from last meeting:

ACTION KendallC: expose our walking tour data to SPARQL querying clients
  ETA before F2F4
ACTION EricP: find logistics re F2F5 at tech plenary in Boston March
  28 Feb - 4 Mar (2 days).  Some WG preference to Mon/Tue of that week.
--> some progress at  
ACTION AlbertoR: owns issue 'DESCRIBE'
ACTION DanC: owner of issue 'yes or no questions' (pending protocol doc)
ACTION KendallC: write a protocol document draft
ACTION DaveB: Update the source section 9, add more formal links,
update the examples, try to think about extra constraints as EricP
proposed (SOURCE ?s and ?s only in in SELECT). Look at various
people's source test cases.
--> some work done at  
ACTION SteveH: own (i.e. propose resolution to) disjunction issue
ACTION SteveH: owns issue 'nested optionals'
	(for the two actions above some discussion happened at the of telecon
           see item 6. disjunction in the agenda)
ACTION PatH review SPARQL def'ns post-publication
ACTION Eric to ask Kendall to put X509 policy use case into UC&R
ACTION EricP: supply definitions for SELECT (vars ordered or not?) ala

Other fulfilled actions:

ACTION SteveH: take rs:size out of expected results from all tests
--> DONE  

2. Services

DanC asked the participants about potential SPARQL services (producers  
and consumers) to demo for XML2004 (too late) or www2005

SteveH has got some computer science datasets made available through a  
RDQL interface - use Rasqal SPARQL implementation is an option to gain  
SPARQL support - possible to demo it for www2005

DaveB has some demos about educational material which might be put  
available under a SPARQL interface

AlbertoR: Asemantics has some SPARQL related demos i.e. take a query  
and generate XML output into an XSLT pipeline - and some SPARQL to iCal  
convertors for news

AndyS: Who is planning to have a client or server over the protocol by  
March?  Not (just) a query engine i.e. where can we work over the web  
between two implementations?
--> SimonR: We'll certainly have it by then.
--> kendall: I'm planning to have a client by March.
--> SteveH: I'l write a ECMASCript client soon after the  
protocol/result format is fixedish

3. W3C Workshop on Semantic Web for Life Sciences debriefing

AndyS and Kendall reported about Life Science workshop in Boston last  
week see http://www.w3.org/2004/07/swls-ws.html

Kendall says that the Life Science community seems needing a technology  
as DAWG SPARQL (query language and protocol)

AndyS says that there is an increasing awareness about RDF and related  
technologies (DAWG also) - but some solutions are still "centralistic"  
and not really fitting the RDF model, especially if need fixed data  

Yoshio: data federation was needed definitely

Kendall: andy: you are right about the variations, but I meant  
specifically the pharma corporations there was variation across the  
whole workshop.

4. Tests (input from Alberto, Steve)

DaveB started to digest some SOURCE test cases as provided by Alberto -  
0198.html - and he also points out that we need a simple vocabulary to  
describe the type of input and output (and query) documents

AndyS: +1 (mildly) to typing input and output

AlbertoR supports RDF/XML as the format for input and output of tests  
even though N3/Turtle syntax is pretty handy to type

patH: Why not publish tests in both formats?
AlbertoR it sounds good idea - manifest.rdf is for RDF/XML while  
manifest.n3 for N3/Turtle

SimonR: +1 to Alberto's comments and really prefer to have only one  
normative version of the tests. But he is alos looking  into Turtle  
patH: if there is only one (normative) then it should be the official  
Yoshio: I respect RDF/XML as a lingua franca

DaveB: won't the urls have to change s/.n3/.rdf/ in all the queries,  
manifests etc.?
AndyS: dave - yes - there will be a chnage of URLs somewhere

DaveB: also Sesame's got a standalone Turtle parser in RIO

AndyS points out that SPARQL spec/document still contains some  
Turtle/N3 syntax vs. RDF/XML i.e. easier triple syntax to read

DanC PROPOSAL: that tests shall have input in RDF/XML and turtle, query  
in SPARQL, output in RDF/XML and turtle, manifest in turtle; manifest  
to be enhanced to explicitly type files --> RESOLVED

ACTION: SteveH is willing to adapt his testing infrastructure to  
generate input/output RDF/XML and typed nodes into manifest file

5. grammar/syntax ($ etc.)

Discussion started about $ vs. ? on variable identifiers

DaveB: last week's straw poll was very much $-favourable
DanC short straw-poll:
	?--> 3 votes
	$ --> 3 votes
	Yoshio: abstains
	kendall: I will object to $ only, I think. FYI.

AlbertoR don't we need $ test cases as well?

ACTION: AndyS to write a test cases which use ? and $ in the same query

SteveH wonders if $foo == ?foo
AndyS: Steve - yes - $ is a marker not part of the variable
AlbertoR: yes

AndyS the SPARQL spec/document will stick to ? but $ will be allowed -  
tests cases will not generally be affected - but some $ tests cases  
will be provided

Discussion continued about comments syntax (single line or multi-line)
DaveB/AndyS RDQL had them all (single and multiline) either C, C++ ( /*  
multi line */ //single line) and #single line style

DaveB is working to implement SPARQL syntax and he found that is  
probably too verbose - we might need some simplifications - like  
avoiding multiple solutions to grammatical options e.g. OPTIONAL vs. []
SimonR: +1 to DaveB's preference for single solutions to grammatical  
SteveH +1 here too

AlbertoR proposed to use QName on variable ?prefix:var - see   

SimonR there has been some offline discussion on IRC today before  
telecon about it with some people - no real consensus reached
SteveH does not like it
AndyS finds it confusing
patH: suggest use a less generic prefix, "var" gets used for  
everything. ?prefix:queryVar?
DaveB: I'll think about it re output xml format

6. disjunction

Steve: my position is to drop disjunction entirely.
DaveB: Steve's proposal  to drop disjunction on 30 Sept at  

AndyS: There are comments asking for disjunction - see comments from  
Geoff Chappell  

DaveB: disjunction cases  from f2f3  

AlbertoR: simple use-case on predicate dc1:title or dc2:title is good  
and simple enough to understand to me (also true we can map that  
"disjunction expression" to some simpler constraints AND  
?pred==dc1:title && ?pred==dc2:title )
kendall: AlbertoR: +1

AndyS: We have implementations - don't understand the case for its hard  
anymore - could someone explain (in email)

ACTION Simon: explain how much of disjuction can be done with  
optionals, nested or otherwise.

7. AOB

ACTION JanneS: will send Jan 4th ftf logistics page

Meeting adjourned at 15:42 UTC

Alberto Reggiori, Senior Partner, R&D @Semantics S.R.L.
alberto@asemantics.com  www.asemantics.com
Milan Office, milano@asemantics.com,   +39 0332 667092
Received on Tuesday, 2 November 2004 21:54:01 UTC

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