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RE: FW: Further comment on SPARQL 1.1 Test Cases

From: Polleres, Axel <axel.polleres@siemens.com>
Date: Tue, 25 Sep 2012 11:02:56 +0200
To: "andy.seaborne@epimorphics.com" <andy.seaborne@epimorphics.com>, "public-rdf-dawg@w3.org" <public-rdf-dawg@w3.org>
Message-ID: <9DA51FFE5E84464082D7A089342DEEE801463C45243F@ATVIES9917WMSX.ww300.siemens.net>
Hi Andy,

Working on my part... Some remarks:

1) Think I spotted a small typo (missing "refer") in
   http://www.w3.org/2009/sparql/docs/query-1.1/rq25.xml#grammarBNodeLabels 
   and have some more clarifying suggestions there

s/
Blank node labels are scoped to the SPARQL Request String in which they occur. 
Use of the same blank node label in a request to the same blank node. 
Fresh blank nodes are generated for each request; blank nodes can not be referenced by label across requests.
/
Blank node labels are scoped to the SPARQL *query or update operation string* in which they occur. 
*Different* use*s* of the same blank node label in a query or update operation *refer* to the same blank node. 
Fresh blank nodes are generated for each request; blank nodes can not be referenced by label across requests.
/



The reason for not speaking about a *request* but rather an *update operation* is that
Given the semantics of updates http://www.w3.org/TR/sparql11-update/#def_datasetQuadPattern
The skolemization, i.e. blank node creation is "per operation", not "per request", thus, 
the same blank node used across different operations within a single request is not necessarily the same.

That is:

 INSERT DATA {GRAPH <g1> {_:b1 :p :o } GRAPH <g2> {_:b1 :p :o } }

(which inserts the same bnode in two graphs)
is IMO *not* the same as

 INSERT DATA {GRAPH <g1> {_:b1 :p :o } } ;
 INSERT DATA {GRAPH <g2> {_:b1 :p :o } }

(which inserts two different bnodes into the two graphs)

Axel

> -----Original Message-----
> From: Andy Seaborne [mailto:andy.seaborne@epimorphics.com] 
> Sent: Freitag, 21. September 2012 12:00
> To: public-rdf-dawg@w3.org
> Subject: Re: FW: Further comment on SPARQL 1.1 Test Cases
> 
> Parts relating to editing of rq25 done.
> 
> 	Andy
> 
> On 20/09/12 09:27, Andy Seaborne wrote:
> >
> >> Summarizing, unless anybody disagrees, I suggest the following:
> >>
> >>   * adapt editorial suggestion 1) as above in Update
> 
> (not done - in the update doc)
> 
> >>   * amend remark 10 in
> >> http://www.w3.org/2009/sparql/docs/query-1.1/rq25.xml#sparqlGrammar
> >>     as suggested above in 2)
> >
> > Yes
> 
> Done
> 
> (longer form used that mentions query and update)
> 
> >
> >>   * Reply to Rob that shared blank nodes across 
> QuadPatterns within 
> >> the same insert are allowed and
> >>     behave as per test case basic-update/manifest#insert-05a
> >
> > Yes
> 
> (This needs to be done.)
> 
> >
> >>   * Optionally, we could add a variant of 
> >> basic-update/manifest#insert-05a to the test
> >>     suite that explicitly covers Rob's example.
> >
> > OK.
> > But we than need to let everyone that has submitted test 
> results about 
> > the change.
> >
> >
> >
> > I think adding a brief note on id scoping is in order as 
> well: Expand
> > 19.6 with
> >
> > """
> > Blank node labels are scoped to the request in which they occur.
> > Use of the the same label referrers to the same blank node. Blank 
> > nodes and fresh blank nodes are generatedA blank label can 
> be used for 
> > each request; blank nodes can not be referenced by label across 
> > documents (requests)
> >
> > Additionally, the same blank node can not be used in two different 
> > basic graph patterns in a SPARQL Query or a SPARQL Update 
> pattern (the 
> > WHERE clause).
> >
> > The same blank node can occur in different QuadData and QuadPattern 
> > clauses.
> > """
> 
> Done - with link as suggested by Axel.
> 
> >
> >      Andy
> >
> >>
> >> Best,
> >> Axel
> >>
> >>
> >> 1.
> >> 
> http://lists.w3.org/Archives/Public/public-rdf-dawg/2012AprJun/0163.h
> >> tml
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> ________________________________
> >>
> >> From: Rob Vesse [mailto:rvesse@dotnetrdf.org]
> >> Sent: Mittwoch, 19. September 2012 20:03
> >> To: Polleres, Axel
> >> Cc: public-rdf-dawg-comments@w3.org
> >> Subject: Re: Further comment on SPARQL 1.1 Test Cases
> >>
> >>
> >> Yes of course you can forward to the list, I will CC this 
> to the list 
> >> myself
> >>
> >> Rob
> >>
> >> From: "Polleres, Axel" <axel.polleres@siemens.com>
> >> Date: Wednesday, September 19, 2012 4:39 AM
> >> To: Rob Vesse <rvesse@dotnetrdf.org>
> >> Subject: RE: Further comment on SPARQL 1.1 Test Cases
> >>
> >>
> >>
> >>          Hi Rob,
> >>
> >>          I realiszed that I sent this to you only offlist. 
> Hope it is 
> >> ok for you if I fwd your suggestions with the WG list?
> >>
> >>          thanks,
> >>          Axel
> >>
> >>
> >> ________________________________
> >>
> >>                  From: Rob Vesse [mailto:rvesse@dotnetrdf.org]
> >>                  Sent: Dienstag, 18. September 2012 18:05
> >>                  To: Polleres, Axel
> >>                  Subject: Re: Further comment on SPARQL 1.1 Test 
> >> Cases
> >>
> >>
> >>                  Hi Axel
> >>
> >>                  Perhaps if the group were to amending the 
> following 
> >> text from 3.1.1 INSERT DATA
> >>
> >>                  Variables in QuadDatas are disallowed in 
> INSERT DATA 
> >> requests (see Notes 8 in the grammar 
> >> <http://www.w3.org/TR/sparql11-query/#sparqlGrammar> ). 
> That is, the 
> >> INSERT DATA statement only allows to insert ground triples. Blank 
> >> nodes in QuadDatas are assumed to be disjoint from the 
> blank nodes in 
> >> the Graph Store, i.e., will be inserted with "fresh" blank nodes.
> >>
> >>
> >>                  And add additional text something like 
> the following:
> >>
> >>
> >>                  Per Note 10 in the grammar blank node identifiers 
> >> may be reused across graph blocks in QuadData but users 
> should note 
> >> that distinct fresh blank nodes will be generated for each 
> usage in 
> >> each block.
> >>
> >>
> >>                  That's a little clunky but I'm sure the 
> WG can come 
> >> up with something a little more flowing that gets the 
> clarification 
> >> across, it's primarily just a case of referring back to 
> that note in 
> >> the main query document.
> >>
> >>
> >>                  Thanks,
> >>
> >>                  Rob
> >>
> >>                                  From: "Polleres, Axel"
> >> <axel.polleres@siemens.com>
> >>                  Date: Tuesday, September 18, 2012 7:48 AM
> >>                  To: Rob Vesse <rvesse@dotnetrdf.org>
> >>                  Subject: RE: Further comment on SPARQL 1.1 Test 
> >> Cases
> >>
> >>
> >>
> >>                          Hi Rob,
> >>
> >>                          Would you have a specific editorial 
> >> suggestion for a respective explaining text which we could 
> add to the 
> >> Update document?
> >>
> >>                          Thanks,
> >>                          Axel
> >>
> >>
> >>
> >> ________________________________
> >>
> >>                                  From: Rob Vesse 
> >> [mailto:rvesse@dotnetrdf.org]
> >>                                  Sent: Freitag, 14. 
> September 2012 17:46
> >>                                  To: Polleres, Axel; 
> >> public-rdf-dawg-comments@w3.org
> >>                                  Subject: Re: Further comment on 
> >> SPARQL 1.1 Test Cases
> >>
> >>
> >>                                  Hi Axel
> >>
> >>                                  Yes this answers my specific 
> >> question but I still think it may be worth the group adding some 
> >> clarifying text to the specification to make the distinction clear
> >>
> >>                                  Rob
> >>
> >>                                                            
>       From:
> >> "Polleres, Axel" <axel.polleres@siemens.com>
> >>                                  Date: Thursday, September 13, 2012
> >> 11:01 PM
> >>                                  To: Rob Vesse 
> >> <rvesse@dotnetrdf.org>, "public-rdf-dawg-comments@w3.org" 
> <public-rdf-dawg-comments@w3.org>
> >>                                  Subject: RE: Further comment on 
> >> SPARQL 1.1 Test Cases
> >>
> >>
> >>
> >>                                          Hi Rob,
> >>
> >>                                          (note that this is not a 
> >> formal reply, but just quickly:)
> >>
> >>                                          > 2 - The 
> restriction does 
> >> not apply to updates
> >>
> >>                                          holds.
> >>
> >>                                          SPARQL1.0 forbade (and
> >> SPARQL1.1 still forbids this blank nodes to be shared 
> across BGPs, cf.
> >>
> >> http://www.w3.org/TR/sparql11-query/#grammarBNodeLabels
> >>
> >>                                          The group didn't see a 
> >> reason to put this restriction on QuadPatterns in the head of 
> >> DELETE/INSERT statements in Update (which are different 
> from BGPs in the WHERE clause).
> >>
> >>                                          Hope this 
> clarifies matters, 
> >> pleases let us know if this answers your request or 
> whether you still 
> >> expect a formal group reply,
> >>
> >>                                          Axel
> >>
> >>
> >>
> >>
> >>
> >> ________________________________
> >>
> >>                                          From: Rob Vesse 
> >> [mailto:rvesse@dotnetrdf.org]
> >>                                          Sent: Freitag, 
> 14. September
> >> 2012 01:39
> >>                                          To:
> >> public-rdf-dawg-comments@w3.org
> >>                                          Subject: Further 
> comment on 
> >> SPARQL 1.1 Test Cases
> >>
> >>
> >>                                          I am working 
> towards getting 
> >> dotNetRDF back to as close to 100% compliance with the 
> current state 
> >> of the SPARQL 1.1 Query and Update specifications as possible and 
> >> have run into one test case which is confusing to me 
> because it seems 
> >> as odd with SPARQL 1.0 behavior.
> >>
> >>                                          This is 
> syntax-update-53.ru:
> >>
> >>
> >>                                          PREFIX :
> >> <http://www.example.org/>
> >>                                          INSERT DATA {
> >>                                                        GRAPH<g1> {
> >> _:b1 :p :o }
> >>                                                        GRAPH<g2> {
> >> _:b1 :p :o }
> >>                                                      }
> >>                                          Currently my 
> implementation 
> >> rejects this on the grounds that the same blank node is reused in 
> >> different graph patterns.  It was my understanding that the 1.0 
> >> specification forbade this and there are in fact a 
> selection of 1.0 
> >> tests that specifically check that a parser rejects such queries.
> >>                                          So I assume one of three 
> >> things must be true:
> >>                                          1 - This restriction has 
> >> been removed in SPARQL 1.1 (if so where does the spec state this?)
> >>                                          2 - The 
> restriction does not 
> >> apply to updates
> >>                                          3 - The test case 
> is incorrect
> >>                                          I would appreciate some 
> >> feedback on this specific test case but also that the 
> working group 
> >> would please make sure the test suite is all up to date 
> and accurate 
> >> (sorry to complain yet about this yet again but it really makes it 
> >> hard to check an implementation if you have to check for 
> each failing 
> >> test whether the test case is actually correct)
> >>                                          Rob
> >>
> >>
> >>
> >
> 
> 
Received on Tuesday, 25 September 2012 09:05:48 GMT

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