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Re: SOURCE test case sketches from users, please?

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Wed, 22 Dec 2004 18:35:54 +0000
Message-ID: <41C9BE8A.5050301@hp.com>
To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Cc: DAWG public list <public-rdf-dawg@w3.org>



Steve Harris wrote:
> On Wed, Dec 22, 2004 at 05:49:00PM +0000, Andy Seaborne wrote:
> 
>>Steve Harris wrote:
>>
>>>Here one of mine [sorry for the lateness]
>>
>>I'm having to catch up :-(
>>
>>
>>>A user wanted to get a list of papers from our computer science research
>>>KB, but he only wanted ones that probably weren't processed by some
>>>heuristics based nataural language software, so hte query (in DAWG speak)
>>>was:
>>>
>>>	SELECT ?id ?title
>>>	WHERE SOURCE ?src (?id dc:title ?title)
>>>			  (?src dc:creator ?creator)
>>>	AND ?creator !~ /^Armadillo/
>>>
>>>assuming a direct relation between the SOURCE node and the document URI,
>>>and
>>>
>>>	SELECT ?id ?title
>>>	WHERE SOURCE ?src (?id dc:title ?title)
>>>		          (?src dawg:source ?doc)
>>>		          (?doc dc:creator ?creator)
>>>	AND ?creator !~ /^Armadillo/
>>>
>>>if not. s/dawg:source/dc:source/ if you prefer
>>
>>Both queries are legal.  Just depends what you decide to put in the default 
>>KB.  You can model your provenance how you like.
>>
>>In either design, ?src is a URI (otherwise you can't put it in a graph) - 
>>bNodes also work apart from GRAPH declarations (which 3Store wouldn't use) 
>>but ?src as a graph does not.
>>
>>Collapsing dawg:source (i.e. design 1) is a matter of do you want to record 
>>other information gainst ?doc that is not true of ?src.  As ever, a more 
>>detailed modelling gets inconvenient in general use.  returning ?src (some 
>>pre-read-in-doc) URI is not going to be what apps usually want.  Unless 
>>they are the data maintenance app, of course!
> 
> 
> Yes, exactly. The problem with collapsing is that it rules out that class
> of data-maintainance task. I agree its somewhat inconvient though, as the
> 2 queries show.
> 
> In defense of the dawg:source style, systems that dont care about
> historical provenance can just assert (<uri> dawg:source <uri>) and get on
> with it.
> 
> I could live with a collapsed form though,

You don't have to!  You-the-DB-designer can choose.  It isn't a WG decision. 
  That's what I meant by both are legal.

	Andy


> I will just have to provide
> some API mechanism to indirect at asserion time for people who need the
> extra level. Which is more or less what I do now, you can specify a graph
> URI (or request a bnode) that is distinct from the resolved URI.
> 
> - Steve
> 
Received on Wednesday, 22 December 2004 18:36:26 GMT

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