David,
What about using <http://www.w3.org/TR/swbp-n-aryRelations/> Defining N-ary
Relations on the Semantic Web Use Case 3 ?
@prefix : < <http://example/mine/address/>
http://example/mine/address/> .
@prefix ex: < <http://example/other/>
http://example/other/> .
@prefix v: < <https://tools.ietf.org/html/rfc6350#section-10.2.6>
https://tools.ietf.org/html/rfc6350#section-10.2.6>
:T78F7E2EB48C044CCB5474C072F5573DB rdf:type :SnailMailAddress, owl:Thing; #
T+GUID
v:SOURCE ex:alice ;
v:FN "Alice Doe" ;
v:ADR "45 Park St, Shadyville, USA" .
Something like that.
Regards, Hans
Hans Teijgeler,
Laanweg 28,
1871 BJ Schoorl,
Netherlands
15926.org
-----Original Message-----
From: David Booth [mailto:david@dbooth.org]
Sent: vrijdag 21 augustus 2015 17:31
To: Paul Houle; semantic-web(a)w3.org; Discussion list for the Wikidata
project.
Subject: Re: Naming Conventions for URIs
On 08/20/2015 11:36 AM, Paul Houle wrote:
[ . . . ]
The production for a QName cannot begin with a number
so it is not
correct to write something like
dbpedia:100
or expect to have the full URI squashed to that. This kind of gotcha
will drive newbies nuts, and the realization of RDF as a universal
solvent requires squashing many of them.
I agree. And although (as Andy pointed out) this particular issue has been
fixed in SPARQL 1.1 and Turtle 1.1, last I checked not all tools had been
upgraded to those specs, so it still remains a problem in practice.
Personally, as a workaround when converting a natural key to a URI, I always
prefix the key with an alpha string that suggests what it is. For example
instead of the above I might write:
dbpedia:dbp_100
Another place that URI creation and management causes unnecessary headache
is when you want to mint a new URI that is relative to an existing URI that
you don't control. For example, suppose someone else gives me a URI for
Alice:
<http://example/other/alice> a foaf:Person .
My software wants to add some triples about Alice's address, such as:
<http://example/other/alice> v:address _:b
_:b v:street "Park St" .
_:b v:city "Shadyville" .
For SPARQL and other reasons it would be better to use a URI like
<http://example/other/alice/address> instead of a blank node _:b for Alice's
address, such as:
<http://example/other/alice>
v:address <http://example/other/alice/address> .
<http://example/other/alice/address> v:street "Park St" .
<http://example/other/alice/address> v:city "Shadyville" .
But since I do not control Alice's URI, I cannot safely mint a URI that is
relative to Alice's URI without the consent of the original URI's owner.
(Otherwise I would be URI squatting, which is bad practice and
risky.)
Intuitively I would like the new URI to be somehow derived from Alice's URI.
I could mint a URI from my own URI space <http://example/mine/>, by
concatenating Alice's URI (after escaping) onto mine, such as:
<http://example/mine/address#http://example/other/alice>
but now I don't have an easy PREFIXed way to write that URI in Turtle or
SPARQL. :( Furthermore, I have to be careful to properly escape the
original URI before concatenating it, because it might contain characters
that are not allowed in a fragment identifier.
In my experience URI allocation and management is one of the most annoying
practical aspects of working with RDF, as compared with JSON, for example,
where one can just put blinders on and ignore the need for global
identification. It would be great if some PhD student or other creative
person could figure out a good solution to reduce this pain and make RDF
easier for a wider audience to use. (New conventions? A new RDF
serialization? Extend RDF?) JSON-LD is a good step, but still doesn't
solve the problem.
David Booth