- From: Polleres, Axel <axel.polleres@siemens.com>
- Date: Mon, 14 May 2012 08:36:33 +0200
- To: David Booth <david@dbooth.org>
- CC: public-rdf-dawg-comments <public-rdf-dawg-comments@w3.org>
Dear David, As for the paragraph you quote: > However, I just noticed the "Note" below that section, which > says that any CREATE may be viewed as immediately followed by a DROP: > [[ > Since (non graph-aware) Graph Stores may remove graphs that > are left empty, for such Graph Stores any CreateOperation may > be viewed as implicitly immediately followed by a > DropOperation (see next subsection), or simply as an > operation with no effect. > ]] Please note that it says explicitly here that "(non graph-aware) Graph Stores may remove graphs *that are left empty* " Thus, existing contents (i.e. non-empty graphs) wouldn't be possibly affected. Please let us know whether this response Addresses/clarifies your concern. Best regards, Axel -- Dr. Axel Polleres Siemens AG Österreich Corporate Technology Central Eastern Europe Research & Technologies CT T CEE Tel.: +43 (0) 51707-36983 Mobile: +43 (0) 664 88550859 Fax: +43 (0) 51707-56682 mailto:axel.polleres@siemens.com > -----Original Message----- > From: David Booth [mailto:david@dbooth.org] > Sent: Friday, 11 May 2012 4:30 PM > To: public-rdf-dawg-comments > Subject: Re: Editorial suggestion for CREATE operation > > I'm looking further at this, and now I am more confused. I > am trying to verify that when a CREATE SILENT operation is > performed on an existing named graph, the content of that > named graph is not changed. This is how I previously > understood it to work and how I think it *should* work. > And when I read the formal semantics of CREATE, I see: > http://www.w3.org/TR/sparql11-update/#defn_createOperation > [[ > OpCreate(GS, iri) = GS union {(iri, {})} if iri not in > graphNames(GS); otherwise, OpCreate(GS, iri) = GS ]] > > If I am reading the above correctly, in this case iri *would* > be in graphNames(GS), so the "otherwise" clause would apply > and the graph store would be unchanged, i.e., the content of > an *existing* named graph should be unchanged. > > However, I just noticed the "Note" below that section, which > says that any CREATE may be viewed as immediately followed by a DROP: > [[ > Since (non graph-aware) Graph Stores may remove graphs that > are left empty, for such Graph Stores any CreateOperation may > be viewed as implicitly immediately followed by a > DropOperation (see next subsection), or simply as an > operation with no effect. > ]] > > But a DROP operation would delete the content of an existing > named graph, so if I am understanding all this correctly, > there seems to be a conflict between this "Note" and the > formal semantics. > > Clarification please? I hope it is the "Note" that is in error. > > Thanks! > David > > > > On Wed, 2012-04-11 at 12:17 -0400, David Booth wrote: > > At http://www.w3.org/TR/sparql11-update/#create > > I suggest adding the sentence: "If the graph already exists > then its > > content is unchanged." > > > > > > -- > David Booth, Ph.D. > http://dbooth.org/ > > Opinions expressed herein are those of the author and do not > necessarily reflect those of his employer. > > >
Received on Monday, 14 May 2012 06:37:03 UTC