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DAWG meeting record 5 July 2005

From: Eric Prud'hommeaux <eric@w3.org>
Date: Wed, 6 Jul 2005 23:26:35 -0400
To: public-rdf-dawg@w3.org
Message-ID: <20050707032635.GA23250@w3.org>
Please inspect
  <http://www.w3.org/2005/07/05-dawg-minutes>
for veracity, particularly, the text
  "Consensus seems to be that we can postpone as long as we don't
  syntactically overconstrain ourselves"
  <http://www.w3.org/2005/07/05-dawg-minutes#bnode_poll>
which I added from memory.

   W3C 

                           Data Access Working Group

5 Jul 2005

   See also: IRC log

Attendees

   Present
          DanC, HowardK, AndyS, EricP, Kendall_Clark, Souri, LeeF,
          SteveH, Elias

   Regrets
          Jeen_Broekstra, Dave_Beckett, Yoshio, FUKUSHIGE

   Chair
          DanC

   Scribe
          Eric Prud'hommeaux

Contents

     * Topics
         1. Convene, take roll, review records and agenda
            http://lists.w3.org/Archives/Public/public-rdf-dawg/2005JulSe
            p/0014.html
         2. SPARQL QL publication
         3. blank node handling... new requirements?
         4. SPARQL protocol publication
     * Summary of Action Items
     _________________________________________________________________



Convene, take roll, review records and agenda
http://lists.w3.org/Archives/Public/public-rdf-dawg/2005JulSep/0014.html

   <DanC> 28 Jun minutes

   PROPOSED accept http://www.w3.org/2005/06/28-dawg-minutes as a true
   record

   RESOLVED

   Next meeting: 12-July

   Next scribe: SteveH

   <scribe> ACTION: EricP add a note that users should be aware of
   non-canonicalization of IRIs [DONE] [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   ericP: warning about identical-looking IRIs -->
   http://www.w3.org/2001/sw/DataAccess/rq23/#WritingSimpleQueries

SPARQL QL publication

   <DanC> ACTION: EricP to refine definitions extraction [CONTINUED]
   [recorded in http://www.w3.org/2005/07/05-dawg-irc]

   <DanC> ACTION: EricP clarify which regex lang, new section ericp; have
   AndyS check it. [CONTINUED] [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   <DanC> ACTION: PatH to review new optionals defintions, if any
   [CONTINUED] [recorded in http://www.w3.org/2005/07/05-dawg-irc]

   <DanC> ACTION: DanC to write SOTD; work with EricP to publish
   [CONTINUED] [recorded in http://www.w3.org/2005/07/05-dawg-irc]

   Andy believes he can produce OPTIONALs text this week in time for PatH
   to review it

blank node handling... new requirements?

   KendallC: we care about bNodes issue, but don't care that it is before
   last call

   <DanC> example from DanC in bnodes

   DanC: at first, I thought bNodes was an overspecification problem. Now
   see that a test case reveals that they want a different definition of
   matching.
   ... (bnode rich stuff can be hard to deal with, yes.
   http://esw.w3.org/topic/IdentifyEverything advises "don't do that".
   hmm.)

   ericP: (multiple identities for everything causes FOAF database bloat)

   <kendall> yes, i agree about "don't do that", but FOAF is kinda a big
   deal!

   [KendallC describes UM's interest in stable bNode identifiers]

   KendallC: I don't want to make a decision here that will make FOAF and
   OWL/DL queries harder in the future

   PatH: we might be able to allow bNodes to pin down a match without
   requiring it

   <DanC> ron's reply regarding the test case

   KendallC: I believe that is what we want. This affects using SPARQL
   between portals

   <DanC> input data: _:l23c14 foaf:mbox <mailto:connolly@w3.org>.

   PatH: in the past, we tried bNodes not treated as variabls
   ... requires that you put a variable there instead.
   ... removes bNodes from the QL entirely
   ... backing off, you can send a query with a bNode but it might not
   match

   Proplems with removing BNodes from SPARQL:

   1. SELECT * gives more bindings

   2. need to rename named bNodes and []s when translating turtle to
   SPARQL

   <DanC> in _:l55c33 , it's an ell, not a one. line 55 character 33.

   <AndyS> 3 ways round it

   PatH: how about some syntax for "marked" bNodes?

   <SteveH> yes

   PatH proposes something that DanC notes appears to match Andy's _!:xyz
   proposal

   AndyS: protocol solution is also interesting 'cause you're in a
   session context

   <AndyS> We also need to relax XML results format (and RDF/XML??)

   <kendall> but that's *one* implementation strategy among others; I
   don't see any reason to privilege it.

   Elias: if we already have the capability, with OPTIONALs, is inventing
   this stuff necessary?

   <EliasT> I meant: what else is going on outside our group that deals
   with bNodes across RDF documents...

   <kendall> Elias: and my answer is foaf & owl dl :>

   AndyS: I don't find the FOAF example so compelling because you can
   always use mbox or mbox_sha1 [FOAF IFPs]
   ... I find update more compelling

   <EliasT> I know FOAF, OWLDL uses bNodes, but I don't know of toolkits
   that can tell you that two bNodes point to the same person... or for
   that fact take a bNodes as an input to their query.

   <DanC> EliasT, there are a number of such toolkits. cwm has a
   "smushing" mode, for example.

   PatH: I find asking the server to create URIs which it is willing to
   author more appealing

   LeeF: that puts a slightly larger burden on the servers that *do*
   offer bNode stability

   AndyS: can be done with a simple map

   KendallC: URI label space solution makes me nervous as I don't know
   the implications on OWL/DL
   ... protocol solution is interesting. want to think about it.
   ... glad we have a record of discussing this.

   <AndyS> Within rq23: FILTER ext:bnodeLabel(?x , "label") - it's mildly
   cheating

   <DanC> DanC suggests we go with the design we have, with some
   flexibility about new information later.

   <kendall> it's all well and good (seriously) to suggest that FOAF
   allows URIs instead of bnodes, as well as definining mbox as IFP, but
   it doesn't seem like OWL DL has that flexibility.

   <SteveH> that doesnt mesh well with CONSTRUCT

   <kendall> It should be possible to query RDF vocabularies that require
   heavy use of bnodes in a user-friendly manner. ?

   <DanC> right, kendall, I think OWL DL does not (though I'm never quite
   sure without looking it up)

   <kendall> eh, that sucks, but ??

   PatH: my intuition is that mapping to URIs has the same implications
   as re-using bNode labels.
   ... but have to think about that hard

   DanC: the effect of adopting Kendall's requirement is that the WG will
   spend weeks considering a technical solution

   JosD: in my experience, I query billions of bNodes and lists and I
   haven't seen this problem come up.

   <SteveH> variable length lists are tricky

   <kendall> jos, i'd welcome you writing an email explaining yr
   experience in this regard

   <LeeF> DanC, does that wording place a requirement on servers to
   support this, or only on the QL to allow clients to ask queries hoping
   that the server supports it?

   <kendall> ericP, i thought we found language in the present spec that
   does *not* allow that presently

   STRAW POLL: who is in favor of a requirement "it must be possible for
   a client to refer to a bnode provided by a server"

   0, -1, -1, +.5, +.5, +.5, +.5, +.5, -1, +1

   <kendall> eh the weakly = .5 thing should be non-canonical, IMO :>

   <patH> Jos, consider a list of children. I query the common children
   of Mary and Bill, and I get back a bnode indicating the list, which
   tells me that some children exist. I want to ask what is in the list.
   How do I refer to it?

   <DanC> do the same query, pat, and add more to it

   <patH> I think the problem we ahve here is that several folk do not
   see that there is a real problem. Suggestion: if non-idiotic users
   (Maryland) say thery have a problem, there really is a problem.

   <kendall> fwiw, i don't know what design instantiates that
   distinction! :>

   <DanC> howardk is excused

   <patH> Add what, Dan? Do I have to put the RDF list syntax into my
   query? (Yech)

   <DanC> yes, yech, but it works, pat

   <patH> OK, sorry, I shuld know better than to say "yech" in an RDF
   context.

   <SteveH> always mapping bnodes into uris is messy

   <SteveH> having it be an option would be more acceptable IMHO

   <kendall> steveh: yes, i understand this as "you may do" instead of
   "you must do"

   <DanC> ok, our decision to go to last call is vacated, and we've got a
   new issue on our issues list.

   <AndyS> Would _!:xyz cover that?

   <JosD> Pat, it is pretty convenient with the ( list ) notation

   <kendall> Andy: splitting the bnode label space seems a variant of
   bnode->uri

   <AndyS> Sort of - but there are not forced to be URIs by design

   <SteveH> kendall, I meant optional at runtime, sorry wasnt clear

   ericP:Of the +5s and 1s, who wants this in this version of SPARQL vs.
   making sure we don't make it difficult in the next version?

   ericP:Consensus seems to be that we can postpone as long as we don't
   syntactically overconstrain ourselves

   <scribe> ACTION: PatH to consider implications of answering bNode
   bindings with created URIs [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   <scribe> ACTION: KendallC to ask Bijan to consider implications of
   answering bNode bindings with created URIs [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   AndyS: ericP, What about the other designs?

   ericP: AndyS, I only pushed on one of them, the one that I saw as most
   immediate

   <SteveH> JosD, you cant use the ( list ) notation in that case because
   of the :nil URI

   <DanC> editors still working on optionals

   <AndyS> I'd like protocol considered because the requirment was for
   session usage

   <scribe> ACTION: JosD to fix up the relevant tests [recorded in
   http://www.w3.org/2005/06/28-dawg-minutes.html#action01] [CONTINUED]

   <JosD> SteveH, what is meant was e.g. query ... { ?X
   owl:interscetionOf (:a :b :c) ...}

   <DanC> syntax-qname-08-rq and syntax-qname-14-rq

   <SteveH> JosD, ah, sorry, I thought you were talking about the unknown
   list length case

   <SteveH> JosD, eg. find all the classes that this class is the
   intersection of, but you dont knwo how many there are

   <DanC> WHERE { :a. x.: : . } <- old or new bits?

   <DanC> old

SPARQL protocol publication

   KendallC: still have a short todo. spending time on query lang.
   ... no complaints apart from Mark Baker

   DanC: what's standing in the way on Results Format?

   EricP: we needed a namespace document. done. don't know what else is
   critical path.

   <kendall> I don't. :>

   <DanC> re results format, EricP notes an outstanding comment about
   xsi:type

   <DanC> xsi:type on sparql:literal elements

   <AndyS> Dave recommedned I remove xsi:schemaLocation=... from example
   in rq23

   <SteveH> I'm happy to add some results test, but it will be at least a
   week before I can do it

   <DanC> (ericp, in the minutes, please continue my 2 actions under the
   Comments item)

   <scribe> ACTION: DanC to put a doc at the new results format namespace
   [CONTINUED] [recorded in http://www.w3.org/2005/07/05-dawg-irc]

   DanC: can one put spurious extra attributes without changing the
   meaning?

   <DanC> ADJOURN.

Summary of Action Items

   [NEW] ACTION: KendallC to ask Bijan to consider implications of
   answering bNode bindings with created URIs [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]
   [NEW] ACTION: PatH to consider implications of answering bNode
   bindings with created URIs [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   [PENDING] ACTION: DanC to put a doc at the new results format
   namespace [recorded in http://www.w3.org/2005/07/05-dawg-irc]
   [PENDING] ACTION: DanC to write SOTD; work with EricP to publish
   [recorded in http://www.w3.org/2005/07/05-dawg-irc]
   [PENDING] ACTION: EricP clarify which regex lang, new section ericp;
   have AndyS check it. [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]
   [PENDING] ACTION: EricP to refine definitions extraction [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]
   [PENDING] ACTION: JosD to fix up the relevant tests [recorded in
   http://www.w3.org/2005/06/28-dawg-minutes.html#action01]
   [PENDING] ACTION: PatH to review new optionals defintions, if any
   [recorded in http://www.w3.org/2005/07/05-dawg-irc]

   [DONE] ACTION: EricP add a note that users should be aware of
   non-canonicalization of IRIs [recorded in
   http://www.w3.org/2005/07/05-dawg-irc]

   [End of minutes]
     _________________________________________________________________


    Minutes formatted by David Booth's scribe.perl version 1.126 (CVS
    log)
    $Date: 2005/07/07 03:14:18 $

-- 
-eric

office: +81.466.49.1170 W3C, Keio Research Institute at SFC,
                        Shonan Fujisawa Campus, Keio University,
                        5322 Endo, Fujisawa, Kanagawa 252-8520
                        JAPAN
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cell:   +81.90.6533.3882

(eric@w3.org)
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Received on Thursday, 7 July 2005 03:26:45 GMT

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