- From: Hammond, Tony <t.hammond@nature.com>
- Date: Thu, 14 Jan 2010 15:27:20 +0000
- To: Bernard Vatant <bernard.vatant@mondeca.com>, Toby Inkster <tai@g5n.co.uk>
- CC: Chris Welty <cawelty@gmail.com>, semantic-web <semantic-web@w3.org>
- Message-ID: <C774E858.21129%t.hammond@nature.com>
> But please don't kill blank nodes ! To kill bnodes would presumably create a requirement to name each and every component of the graph which seems onerous to say the least. Unless there were something like global unnamed properties, i.e. ³knwon unknowns². Maybe Rumsfeld was on to something: ³There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we now know we don¹t know. But there are also unknown unknowns. These are things we do not know we don¹t know.² Cheers, Tony On 14/1/10 15:03, "Bernard Vatant" <bernard.vatant@mondeca.com> wrote: > Hi all > > Agreed with many points said > > - Don't fix what is not broken > - Get rid or let die obscure constructions such as bags and reification > - Simplify, simplify, simplify :) > > But please don't kill blank nodes ! > > My use case (not academic, used on a daily basis) is translation from a model > to another using SPARQL CONSTRUCT. Such translations (but it is yet another > story to be discussed in another thread) are a very powerful way to pass from > a model to another, without mapping declarations or commitments from either > side. > > Exemple > > Graph 1 is a document data base using foaf:Document class with Dublin Core > attributes such as dcterms:creator and dcterms:subject > Graph 2 is a data base of expertises using a ex:Expertise class with object > properties ex:expert, ex:topic and ex:supportDocument > > I can construct instances of ex:Expertise in G2 out of instances of > foaf:Document in G1, but I have no URI in G1 for those. So I need bnodes in my > query, such as : > > CONSTRUCT { _:x a ex:Expertise. > _:x ex:expert ?p. > _:x ex:topic ?t. > _:x ex:supportDoc ?d} > > WHERE { ?d a foaf:Document. > ?d dcterms:creator ?p. > ?d dcterms:subject ?t } > > Unless SPARQL provide ways to generate URIs on the fly for my ex:Expertise > instances. But I don't think it does. > > Seems very specific, but think about it before killing bnodes. Or provide > something similar w/o them. > > > Bernard > > > 2010/1/14 Toby Inkster <tai@g5n.co.uk> >> On Wed, 2010-01-13 at 11:00 -0500, Chris Welty wrote: >>> > I suppose we don't really need to discuss whether we should >>> > investigate an "RDF 2.0", but rather what kinds of requirements >>> > various RDF users have that they would like to be considered (I'd like >>> > this thread to be less "+1" and "-1" messages, and more "I'd like to >>> > see RDF support x...") >> >> Adopt SPARQL's data model for all future Semantic Web standards -- for >> all SW protocols and serialisations. >> >> The major differences between SPARQL's data model and RDF are: >> >> * Explicit support for named graphs >> * Literal subjects >> * Blank node predicates >> >> (Though it might be a good idea to phase out blank nodes.) >> >> -- >> Toby A Inkster >> <mailto:mail@tobyinkster.co.uk> >> <http://tobyinkster.co.uk> >> >> > > ******************************************************************************** DISCLAIMER: This e-mail is confidential and should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage mechanism. Neither Macmillan Publishers Limited nor any of its agents accept liability for any statements made which are clearly the sender's own and not expressly made on behalf of Macmillan Publishers Limited or one of its agents. Please note that neither Macmillan Publishers Limited nor any of its agents accept any responsibility for viruses that may be contained in this e-mail or its attachments and it is your responsibility to scan the e-mail and attachments (if any). No contracts may be concluded on behalf of Macmillan Publishers Limited or its agents by means of e-mail communication. Macmillan Publishers Limited Registered in England and Wales with registered number 785998 Registered Office Brunel Road, Houndmills, Basingstoke RG21 6XS ********************************************************************************
Received on Thursday, 14 January 2010 15:27:58 UTC