W3C home > Mailing lists > Public > public-rdf-wg@w3.org > April 2012

Re: New Proposal (6.1) for GRAPHS

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 4 Apr 2012 11:18:22 +0100
Cc: public-rdf-wg@w3.org
Message-Id: <A731C0CA-E3DF-4388-91FE-E0FF2C06B48A@garlik.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
On 2012-04-04, at 08:25, Andy Seaborne wrote:
> 
> On 03/04/12 01:27, Sandro Hawke wrote:
>>>> There's some misunderstanding here, yes.   Maybe you can talk through
>>>> >  >  some particular thing you imagine doing, involving merging and TriG, and
>>>> >  >  I'll be able to pick it up.   From what you've written, I'm confused.
>>>> >  >
>>>> >  >  Maybe I can clarifying by translating this TriG document:
>>>> >  >
>>>> >  >            <u1>    {<a>    <b>    <c>   }
>>>> >  >
>>>> >  >  into this English declaration:
>>>> >  >
>>>> >  >            The URI 'u1' denotes something, and that thing has exactly one
>>>> >  >            associated RDF Graph.   That associated RDF graph consists of
>>>> >  >            one RDF triple, which we can write in turtle as "<a>   <b>   <c>".
>>> >
>>> >
>>> >  Clearer, but not what I would have expected.
>>> >
>>> >  Why "exactly one associated RDF Graph"?
>> My intuition is that there are important thing you can't do if you allow
>> more than one graph to be associated with the named object, but I
>> haven't really explored that because SPARQL datasets clearly allow only
>> one GRAPH for a given name, so I figured we'd stick with that.  That's
>> why I said hasGraph was a functional property.
> 
> A query executes at some (idealized) point in time, and a query closes the world to execute (or they'd never complete!).   An RDF Dataset is the local concept for the data being queried - there's no statement about anything outside the local context made, or needed for SPARQL.

+1

This is an important distinction.

- Steve

-- 
Steve Harris, CTO
Garlik, a part of Experian
1-3 Halford Road, Richmond, TW10 6AW, UK
+44 20 8439 8203  http://www.garlik.com/
Registered in England and Wales 653331 VAT # 887 1335 93
Registered office: Landmark House, Experian Way, Nottingham, Notts, NG80 1ZZ
Received on Wednesday, 4 April 2012 10:19:05 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 22:02:03 UTC