W3C home > Mailing lists > Public > semantic-web@w3.org > July 2010

Re: RDF 2.0 Wishlist - Legal RDF which I can't SPARQL

From: Paul Gearon <gearon@ieee.org>
Date: Thu, 29 Jul 2010 13:13:18 -0400
Message-ID: <AANLkTin_3YVw2vibt_UprJavpScmt_0=f9obZZo4eaH+@mail.gmail.com>
To: Mischa Tuffield <mischa.tuffield@garlik.com>
Cc: Damian Steer <pldms@mac.com>, Semantic Web <semantic-web@w3.org>
On Thu, Jul 29, 2010 at 12:38 PM, Mischa Tuffield
<mischa.tuffield@garlik.com> wrote:
>> As for being queried in SPARQL, that's a relative concept. Yes, you
>> can't match it directly, as you've pointed out, but it can still be
>> returned in results (unless an implementation specifically tries to
>> put the data into an internal IRI and a validation error occurs, but
>> that's implementation specific). It's always possible to bind it to a
>> variable and return the data. Alternatively, if you really did want to
>> search for it, you could bind to a variable, and FILTER on its string
>> representation. Yes, it will be slow, but my point is that the
>> language isn't *completely* deficient (complain to Steve if it is).
>> ;-)
>
> I understand that I can query the RDF using sparql and I can bind it to a
> variable to get the URI returned. I stumbled upon this because I was doing a
> "insert data {graph <http://example.com/graph> { ,
> <http://example.com/foo'bar> foo:Property "something" . }" as per the sparql
> update work, which I can't really do the bind trick with, but I didn't want
> to use that as an example as the sparql people are not finished with their
> work.

Officially, you're right, it's not finished. However, that's not going
to change, so it's probably worth mentioning.

In a hack similar to the one I mentioned with FILTER, but you can always say:

insert { graph <http://example.com/graph> {
  ?u  foo:Property  "something" } }
{ { select IRI("http://example.com/mylamefoafdocument`uri") as ?u {} } }

But then I realized that this uses a non-standard constructor for
IRIs! I should raise this as a possible function for SPARQL 1.1.

> But yes point taken, I have already moaned about this with Steve (and trust
> me I do bug him the whole time), I guess I will probably end up poking the
> sparql wg about this.

I don't think of this as a SPARQL issue so much as an RDF issue.
SPARQL was trying to be forward compatible when it selected IRIs, and
accepting URIRefs would seem to be a backward step. Instead, the RDF 2
WG (if one goes ahead) should look to move to IRIs, and indeed this is
on the table.

Regards,
Paul Gearon
Received on Thursday, 29 July 2010 17:13:46 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:42:21 UTC