- From: Ivan Herman <ivan@w3.org>
- Date: Wed, 03 Mar 2010 13:26:04 +0100
- To: Lee Feigenbaum <lee@thefigtrees.net>
- CC: SPARQL Working Group <public-rdf-dawg@w3.org>
- Message-ID: <4B8E555C.6040004@w3.org>
Hi Lee, first of all, thanks a lot for this write up. It was very helpful (at least to me). On 2010-3-3 07:16 , Lee Feigenbaum wrote: [snip the explanation to save space] > > == The Proposals == > > I see only two realistic proposals emerging from this. > > 1/ We prohibit blank nodes in the DELETE template completely. > > 2/ Blank nodes in DELETE templates act as "wild cards"--effectively > variables pre-bound to all RDF terms--to let us write some shortcuts and > handle Sandro's case of deleting RDF lists. We prohibit the same blank > node label from being used in multiple scopes. > > > > == My Opinion == > > While I'm sympathetic to Sandro's use case, I'm frightened of the fact > that: > > DELETE { _:b1 :p :o } WHERE { } > and > DELETE { ?b1 :p :o } WHERE { } > > do dramatically different things. Because of this, I'd rather we go with > the first proposal and prohibit blank nodes in the DELETE template > entirely. I think Sandro's use case is important. Eg, this is the only way we can manipulate, via SPARQL UPDATE, RDF graphs encoding OWL constructs or, if Sandro's RIF-in-RDF encoding is done, RIF rules. With entailment regimes around the corner, I think this is important. (And yes, as you say, the restriction on non-named blank nodes is difficult to justify.) I actually do not find your example so confusing. The only point where people might be confused, probably, is that DELETE {_:a :b :c } is disallowed. But that can be explained. Ie, I would prefer to go with solution (2) as described above. > > hope this is helpful, As I said, very. Thanks! Ivan > Lee > > > > > -- Ivan Herman, W3C Semantic Web Activity Lead Home: http://www.w3.org/People/Ivan/ mobile: +31-641044153 PGP Key: http://www.ivan-herman.net/pgpkey.html FOAF : http://www.ivan-herman.net/foaf.rdf vCard : http://www.ivan-herman.net/HermanIvan.vcf
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Received on Wednesday, 3 March 2010 12:26:02 UTC