- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Thu, 03 Mar 2011 15:35:54 +0000
- To: SPARQL Working Group <public-rdf-dawg@w3.org>
What are people's current thoughts about bnodes and DELETE templates? The only UC seems to be deleting fixed length lists. Are there any others? DELETE { ?x :p (1 2 3) } WHERE { ..find ?x .. } rather than something like (this should works on arbitrary length lists). --------------- DELETE { ?z rdf:first ?head ; rdf:rest ?tail . } WHERE { .. find ?x .. ?x :p ?list . ?list rdf:rest* ?z . ?z rdf:first ?head ; rdf:rest ?tail . } ; # Delete the triples that connect the lists. DELETE WHERE { ?x :p ?y . } --------------- Not ideal, especially as it does not combine easily, adding DELETE { ?x :p (1 2 3) . ?x rdf:type :XType . } WHERE { ..find ?x .. } so there is a risk "find ?x" will need to be repeated. My preference is currently to make a syntax restriction that bnodes can't be in DELETE templates (ditto DELETE WHERE) so a future WG can relax that and decide. That's "Option4: is to forbid bnodes in DELETE" from the last telecon. where "forbid" is make it a syntax error, done by adding an addition note to the grammar, rather than making the grammar have the productions for a triple block without bnode possibilities. This is how INSERT DATA vs INSERT is done. ==== Strawpoll summaries: The strawpool this time and last time hasn't been conclusive: Option 1: Bnode match all resources in the graph (essentially rewriting 1 in the mails) Option 2 : bnodes match whatever they match if treated as "modify_template copied to body" Option 3: treat bnodes as in CONSTRUCT/INSERT, i.e. as new bnodes... would mean they don't match anything. Option 4:is to forbid bnodes in DELETE Telecon: March 1: [bglimm] 3 or 4 [pgearon] option 4 (followed by 3) [kasei] 0 [sandro] (sorry, undecided.) [AndyS] no opinion - need to see details. [OlivierCorby] don't know yet [AxelPolleres] prefer 1 over 2 , but can live with 3/4 and the time before: Telecon Feb 22: STRAWPOLL: option 1, 2, or 3? ← <pgearon> 3 <NickH> 3 <bglimm> undecided <kasei> 0 <sandro> undecided <MattPerry> 0 <cbuilara> 0 <AxelPolleres> 1 or2 (but can live with 3) Andy
Received on Thursday, 3 March 2011 15:36:37 UTC