Re: [GRAPHS] Follow your graph nose.

Hi Fabien,

On 2 Mar 2011, at 13:04, Fabien Gandon wrote:
> An other issue that was touched in the discussions about IRI to identify g-boxes/graphs/etc. is the application of the follow your nose principle of linked data to RDF graph [1].
> 
> As I remember from the workshop there were at least two opinions on that matter:
> 
> Opinion (1) : When I follow the IRI of a graph I should get a serialization of the triples contained in that graph.
> 
> Opinion (2) : When I follow the IRI of a graph I should get triples about that IRI.
…
> If I had to chose, I would prefer option (2) to have a more consistent behavior and remain independent of the type of resource identified by the IRI i.e. whether it is a graph or not I always get triples *about* the IRI / Resource.

As I said in the call today, I think that (1) is consistent with linked data practice. Whether or not to *additionally* include some statements about the graph IRI in the returned graph (your option (3)) is a tactical decision that's up to the user.

Let me explain with the example of DBpedia, which is a paragon of implementing the Linked Data principles.

  http://dbpedia.org/resource/Berlin

When you do a GET on this resource, you don't get any triples back. Instead, you are 303-redirected to *another* resource:

  http://dbpedia.org/data/Berlin.rdf

That URI identifies an RDF document describing Berlin. Do a GET on it, and you'll get triples. These triples describe *both* /resource/Berlin (the city) *and* /data/Berlin.rdf (the RDF document).

If you like, you can see /data/Berlin.rdf as a graph URI (g-box in Sandro's language).

This is explained in detail in any number of documents that explain the basics of linked data. Here are some:

  http://www.w3.org/TR/cooluris/
  http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/
  http://linkeddatabook.com/editions/1.0/#htoc8

The intuition is that the Web of Linked Data consists of g-boxes named by URIs. Each g-box describes one or more resources (maybe including itself). You also assign URIs to other things such as people or cities. When you assign a URI to something that's not a g-box nor another kind of web resource, then you configure the URI so that it redirects to a g-box that describes that thing. (Or you append a fragment “#something” to a g-box URI.)

(There's a risk that this message will spawn a long thread about httpRange-14 and non-information resources. After 300 messages it will be concluded that it's a really complex topic and that it's actually not relevant to the work of this WG. I apologize in advance for this, and blame Fabien for starting it. ;-)

Best,
Richard

Received on Wednesday, 2 March 2011 23:05:51 UTC