- From: David Booth <david@dbooth.org>
- Date: Thu, 13 Dec 2012 12:27:38 -0500
- To: Bernard Vatant <bernard.vatant@mondeca.com>
- Cc: Pat Hayes <phayes@ihmc.us>, semantic-web <semantic-web@w3.org>
hi Bernard, On Thu, 2012-12-13 at 10:48 +0100, Bernard Vatant wrote: > Dear all > > I'm 100% with Pat here in the defence of blank nodes, as ever [1] > The more I'm using RDF daily, the more I love them, and seems to me > you miss a lot of RDF expressivity by wanting everything to be > uniquely identified by a URI > Just another example : "John met a girl yesterday in a cafe". > Are you going to coin a URI for those ill-identified girl, cafe, and > event? Certainly not. But you want to record this information in > John's bio because you guess it's likely to be of some importance > later in his life, even if so far you don't know more about it. > > The "natural" expression of things in RDF is that some event in the > life of John took place yesterday, involving some girl in some cafe. > > @prefix bio:<http://vocab.org/bio/0.1/> > @prefix foaf:<http://xmlns.com/foaf/0.1/> > @prefix schema:<http://schema.org/> > > :John bio:event _:someEvent . > _:someEvent bio:Date '2012-12-12' . > _:someEvent bio:Participant _:someGirl . > _:someEvent bio:place _:someCafe . > _:someGirl a foaf:Person . > _:someGirl foaf:gender 'female' . > _:someCafe a schema:CafeOrCoffeeShop . > Well Behaved RDF does not prohibit blank nodes, it just constrains their use to avoid problems. The example above *is* Well Behaved RDF. It could have been written in Turtle using only implicit blank nodes: :John bio:event [ bio:Date "2012-12-12" ; bio:Participant [ a foaf:Person ; foaf:gender "female" ] ; bio:place [ a schema:CafeOrCoffeeShop ] ] . -- 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 Thursday, 13 December 2012 17:28:08 UTC