- From: Paul Houle <ontology2@gmail.com>
- Date: Thu, 20 Aug 2015 11:36:29 -0400
- To: "semantic-web@w3.org" <semantic-web@w3.org>, "Discussion list for the Wikidata project." <wikidata-l@lists.wikimedia.org>
- Message-ID: <CAE__kdQnTKVtECJ9Bj=Xh7Gid7Kx4AMv=TBpybPStOUzyCK0KQ@mail.gmail.com>
Tell me if I am right or wrong about this. If I am coining a URI for something that has an identifier in an outside system is is straightforward to append the identifier (possibly modified a little) to a prefix, such as http://dbpedia.org/resource/Stellarator Then you can write @prefix dbpedia: <http://dbpedia.org/resource/> and then refer to the concept (in either Turtle or SPARQL) as dbpedia:Stellarator. I will take one step further than this and say that for pedagogical and other coding situations, the extra length of prefix declarations is an additional cognitive load on top of all the other cognitive loads of dealing with the system, so in the name of concision you can do something like @base <http://dbpedia.org/resource/> @prefix : <http://dbpedia.org/ontology/> and then you can write :someProperty and <Stellarator>, and your queries are looking very simple. 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. Another example is isbn:9971-5-0210-0 If you look at the @base declaration above, you see a way to get around this, because with the base above you can write <100> which works just fine in the dbpedia case. I like what Wikidata did with using fairly dense sequential integers for the ids, so a dbpedia resource URI looks like http://www.wikidata.org/entity/Q4876286 which is always a QName, so you can write @base <http://www.wikidata.org/entity/> @prefix wd: <http://www.wikidata.org/entity/> and then you can write wd:Q4876286 <Q4876286> and it is all fine, because (i) wikidata added the alpha prefix and (ii) started at the beginning with it, and (iii) made up a plausible explanation for it is that way. Freebase mids have the same property, so :BaseKB has it too I think customers would expect to be able to give us isbn:0884049582 and have it just work, but because a number is never valid in the QName, you can encode the URI like this: http://isbn.example.com/I0884049582 and then write isbn:I0884049582 <I0884049582> which is not too bad. Note, however, if you want to write <0884049582> you have to encode as http://isbn.example.com/I0884049582 because, at least with the Jena framework, the same thing happens if you write @base <http://isbn.example.com/I> or @base <http://isbn.example.com/> so you can't choose a representation which supports that mode of expression and a :+prefix mode. Now what bugs me is, what to do in the case of something which "might or might not be numeric". What internal prefix would find good acceptability for end users? -- Paul Houle *Applying Schemas for Natural Language Processing, Distributed Systems, Classification and Text Mining and Data Lakes* (607) 539 6254 paul.houle on Skype ontology2@gmail.com :BaseKB -- Query Freebase Data With SPARQL http://basekb.com/gold/ Legal Entity Identifier Lookup https://legalentityidentifier.info/lei/lookup/ <http://legalentityidentifier.info/lei/lookup/> Join our Data Lakes group on LinkedIn https://www.linkedin.com/grp/home?gid=8267275
Received on Thursday, 20 August 2015 15:36:56 UTC