Re: named graphs (was Re: Data URIs)

One of the issues with named graphs is that they are not nestable. It  
might be considered rude for OWL to squat on the single named graph  
namespace. Until there is a proposal for nesting graphs, using named  
graphs in OWL would preclude loading and OWL ontology in to a  
specific named graph that a user has.

On Jul 2, 2008, at 3:10 PM, Sandro Hawke wrote:

>> I'm finding them more and more appealing. So, supposed I have an  
>> axiom:
>>     <owl:ObjectProperty rdf:about="#has_direct_part">
>>          <rdfs:subPropertyOf rdf:resource="#has_part"/>
>>      </owl:ObjectProperty>
>> And I want to annotate it. I'm proud of it. Here's a data uri:
>> <data:application/rdf+xml,%3C%3Fxml%20version%3D%221.0%22%3F%3E%0A% 
>> 3C%
>> 21DOCTYPE%20rdf%3ARDF%20%5B%0A%20%20%20%20%3C%21ENTITY%20owl%20% 
>> 22http
>> %3A//
>> 20owl2%20%22http%3A//
>> 20%3C%21ENTITY%20xsd%20%22http%3A// 
>> 20%
>> 3E%0A%20%20%20%20%3C%21ENTITY%20owl2xml%20%22http%3A//
>> 2006/12/owl2-xml%23%22%20%3E%0A%20%20%20%20%3C%21ENTITY%20rdfs%20%
>> 22http%3A// 
>> 20%3C
>> %21ENTITY%20rdf%20%22http%3A//
>> 22%20%3E%0A%20%20%20%20%3C%21ENTITY%20worm-wikipedia%20%22http%3A//
>> wikipedia.owl
>> %23%22%20%3E%0A%5D%3E%0A%3Crdf%3ARDF%20xmlns%3D%22http%3A//
>> wikipedia.owl
>> %23%22%0A%20%20%20%20%20xml%3Abase%3D%22http%3A//
>> 7Ebparsia/ontologies/2008/anatomy/worm-wikipedia.owl%22%0A%20%20%20%
>> 20%20xmlns%3Aowl2xml%3D%22http%3A//
>> 0A%20%20%20%20%20xmlns%3Aworm-wikipedia%3D%22http%3A//
>> wikipedia.owl
>> %23%22%0A%20%20%20%20%20xmlns%3Axsd%3D%22http%3A//
>> XMLSchema%23%22%0A%20%20%20%20%20xmlns%3Aowl2%3D%22http%3A//
>> 22http%
>> 3A//
>> 3D%22http%3A//
>> 20%20xmlns%3Aowl%3D%22http%3A//
>> 20%20%20%3Cowl%3AOntology%20rdf%3Aabout%3D%22%22%3E%0A%20%20%20%20% 
>> 3C/
>> owl%3AOntology%3E%0A%20%20%0A%20%20%20%20%3Cowl%3AObjectProperty% 
>> 20rdf
>> %3Aabout%3D%22%23has_direct_part%22%3E%0A%20%20%20%20%20%20%20%20%
>> 3Crdfs%3AsubPropertyOf%20rdf%3Aresource%3D%22%23has_part%22/%3E%0A% 
>> 20%
>> 20%20%20%3C/owl%3AObjectProperty%3E%0A%3C/rdf%3ARDF%3E>
>> Ok, I hear the laughter and the shrieks of outrage :)
>> This wasn't the nicest serialization*, but it works. It's reversible.
>> And now we have a URI for an RDF subgraph. data uris are implemented
>> in major browsers and have an ITEF RFC. They clearly are not for hand
>> authoring or reading, but neither is reification. If we chose
>> ntriples or turtle as the base, it would be somewhat terser. If we
>> have a normalization, we could be pretty sure of getting the same URI
>> for the same syntactic expression (trickiness there!). You can use
>> that anywhere you'd use an URI, so the subject or object of a triple.
>> It would nest (double encoding doesn't cause a blowup.
>> Using literals is a bit easier to write by hand.
> I don't have a strong opinion about these different approaches, but I
> think we should be clear that these are primarily interim designs for
> use until there's a standard format for RDF with named graphs.  And we
> should make sure whatever approach we pick can be compatible with a
> future named-graphs standard, so OWL 2 wont have to change: there will
> be the RDF/XML serialization (using one of these interim hacks) and  
> the
> RDF/XML+NamedGraphs serialization that doesn't need such hacks.
> As far as I can tell, there is consensus in the RDF community that  
> there
> should be a named-graph standard.  Making such a standard is,
> unfortunately, an awkwardly-sized peice of work.  It doesn't really  
> fit
> inside any other work, and it's rather small for a whole new Working
> group.  So I don't know exactly when/how it will happen.
>    -- Sandro

Received on Wednesday, 2 July 2008 19:18:48 UTC