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Re: URI aliases for RDF terms?

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 2 Nov 2011 10:16:59 +0000
Cc: W3C RDF WG <public-rdf-wg@w3.org>
Message-Id: <9578D8B2-5BD1-4014-824D-67B96B92349B@garlik.com>
To: Ivan Herman <ivan@w3.org>
Does it have to be a URI? What about using "a" as in Turtle, or "type"? Makes it more obvious that it's an alias, not a URI.

I think using http://something.example/type and silently transforming it to http://www.w3.org/1999/02/22-rdf-syntax-ns#type will be confusing for users. Especially if real-world systems use both in practice.

It could also be defined as an entity in HTML5, e.g.

<!ENTITY type "http://www.w3.org/1999/02/22-rdf-syntax-ns#type">

then it's just

<link itemprop="&type;" href="http://type.example.org" />

- Steve

On 2 Nov 2011, at 09:43, Ivan Herman wrote:

> I thought that this working group needs some more discussions, because we have already solved all our issues:-)
> 
> More seriously: there is an issue on which this WG, maybe, could/should have an opinion. There is a long discussion going on in the Data in HTML SWIG Task Force[1], while looking at the microdata->RDF mapping. The issue is around the ugly URI that one has to use for rdf:type...
> 
> [[[
> Background:
> 
> - at present, an item in microdata can only have one type, that is syntactically accepted via their @itemtype attribute
> - people have expressed the need to have several types for a single entity
> - the only way to do it now is to explicitly 'encode' a type in microdata, something like
> 
> <link itemprop="http://www.w3.org/1999/02/22-rdf-syntax-ns#type" href="http://type.example.org" />
> 
> - there is no way in microdata to abbreviate a URI with a prefix:extension syntax, ie, to be able to write rdf:type. In other terms, users _must_ write down the full URI. Let us face it, nobody can remember that stuff (I know I can't:-)
> - the solution that is emerging is to define a separate 'type' attribute in, say, schema.org, ie, that people could say
> 
> <link itemprop="http://schema.org/type" href="URI-to-Type" />
> 
> because people might remember that more easily (which is true). Then... I presume microdata->RDF mappings would have to _know_ that particular attribute and turn it into rdf:type. This is really ugly, but that is the direction things seem to go.
> (- of course, the proper solution would be for microdata to allow several types in one statement (like RDFa allows). But the microdata community is reluctant to do that.)
> ]]]
> 
> This discussion does raise a more general issue, however: does it make sense for us to think in terms of URI aliases for the RDF(S) terms? Something like http://www.w3.org/rdf/type, or something similar. It would make the human authoring of RDF easier (even if all RDF syntaxes allow for some sort of a prefix definition, which greatly alleviates the problem).
> 
> I realize this may be a huge can of worms, in terms of deployed applications, specifications, etc. In other words, probably the only way to do that would be to define some sort of a canonical alias? redirection? etc, of humanly readable URI-s to the current ones. And even that may be hairy. But it may be worth some discussions...
> 
> Thanks
> 
> Ivan
> 
> 
> [1] http://www.w3.org/wiki/Html-data-tf
> 
> 
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
> 
> 
> 
> 
> 
Received on Wednesday, 2 November 2011 10:18:12 GMT

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