News for hackers. Stuff that matters.

A comment on Publishing JSON-LD for Developers. Parent comment

Re:Publishing JSON-LD for Developers by titanix2 on Tuesday May 08, 2018 @08:41PM (#17026607)
I'll reply to you without quoting everything to make it more readable. First, the paper is already accepted and is not about RDF per se. I know about the serialization formats and none of them will fit my needs because the problem lies in the data model, not a concrete syntax. I don't really understand the point you try to make about literals. Mine is that because literals cannot be the origin of an edge, they form sinks. And that's very annoying for building a graph (of strings) because you then need to create proxy nodes for data all the way up.

For annotations, you can read[1]. What I meant however a really simple graph construct: information on edges. In the Neo4j lingo that is called a property[2]. There absence in RDF make it difficult to represent situations such "Paris"---distance:54---"Rennes". I'm visibly not the only one it's itching[5].

Yes you can use URN, be some projects doesn't support them. Check out the linguistics data cloud[3] for an example with such a requirement. Moreover, renting a domain (you can't buy a domain name) may be cheap but why putting this burden on yourself if you can avoid it? Even Microsoft mess up with them[4] for time to time. I read some papers of 2 years old and all the endpoints and links where dead. So yes, if you're not doing a web project, no need for a web format. Sadly this is what is done in my field.

Anyway I'll be curious to see something you built with RDF, if any. I failed to find your work besides two papers that aren't related to the subject.

[1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.352...

[2] https://graphaware.com/neo4j/2013/10/24/neo4j-qualifying-rel...

[3] http://linguistic-lod.org/

[4] https://www.theregister.co.uk/2003/11/06/microsoft_forgets_t...

[5] http://dbooth.org/2010/rdf2/

[ Parent | on HN ]
Re:Publishing JSON-LD for Developers by igravious on Tuesday May 08, 2018 @11:30PM (#17027243)
> I know about the serialization formats and none of them will fit my needs because the problem lies in the data model, not a concrete syntax. I don't really understand the point you try to make about literals.

So create your own serialization format suited to your own needs.

> I don't really understand the point you try to make about literals. Mine is that because literals cannot be the origin of an edge, they form sinks. And that's very annoying for building a graph (of strings) because you then need to create proxy nodes for data all the way up.

If by origin you mean what RDF calls subject then yes, as I said, the RDF data model does not support subject literals. That is by design. What you could do is create a resource that encapsulates strings in the way you want a use that for both the subject and object. Don't think them as proxy nodes, think of it like you now have the ability decorate your string literals in an extensible way.

> For annotations, you can read[1]. What I meant however a really simple graph construct: information on edges. In the Neo4j lingo that is called a property[2]. There absence in RDF make it difficult to represent situations such "Paris"---distance:54---"Rennes".

    PREFIX distance: <http://www.my_cool_domain.fr/prop/distance>

   [wdt:Q90 distance:354 wdt:Q647]
Because Paris and Rennes are already in Wikidata, why not use them? Create your own namespace, call the distance property "distance" when you're prefixing it, reserve numerals in this property to signify geographical magnitude in km. 354 between Paris and Rennes, not 54?

> I'm visibly not the only one it's itching[5].

Two wrongs don't make a right. Considering that link was calling for this in 2010 suggest to me that you oughtn't hold your breath. Also them self-describing as an expert is crass.

> Yes you can use URN, be some projects doesn't support them.

Well, that is not the fault of RDF now is it?

> Moreover, renting a domain (you can't buy a domain name) may be cheap but why putting this burden on yourself if you can avoid it?

If you can't afford €10 per year or the institution where your project is located can't afford it then you have bigger problems than imaginary RDF restrictions.

> Anyway I'll be curious to see something you built with RDF, if any. I failed to find your work besides two papers that aren't related to the subject.

I've used Wikidata and DBpedia to build a corpus of philosophers and their philosophical texts without too much of a problem once I wrapped my head around how RDF and SPARQL work.

Paris on Wikidata: https://www.wikidata.org/wiki/Q90

Rennes on Wikidata: https://www.wikidata.org/wiki/Q647

[ Parent | on HN ]
Re:Publishing JSON-LD for Developers by titanix2 on Wednesday May 09, 2018 @05:39PM (#17034393)
You are changing the problem at hand. It is not how to create a distance relation, it is how to add more data to an existing edge. To do that in RDF you need reification, which is notoriously painful[1]. Moreover <http://www.my_cool_domain.fr/prop/distance54> is not equal to "54" and 54 cannot be inferred from it because URI are opaques. In addition, you have now a totally different property than those of every pair of cities that are not 54 km afar. So, RDF have some strengths and good points but in the current case it is creating unnecessary problems to encode a very simple situation.

[1] https://www.safaribooksonline.com/library/view/practical-rdf...

[ Parent | on HN ]