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Re: [UCR] alternative Use case publication

From: Dave Reynolds <der@hplb.hpl.hp.com>
Date: Tue, 21 Mar 2006 18:13:37 +0000
Message-ID: <44204251.1010706@hplb.hpl.hp.com>
To: axel@polleres.net
CC: public-rif-wg@w3.org

Axel Polleres wrote:

> Dave Reynolds wrote:

>> - either delete or rephrase the value-judgement-full statement:
>> [[[
>> Recursive dependencies among the interlinked rulesets greatly extend 
>> and generalize the simple one-way RDF data access via SPARQL.
>> ]]]
>> Sparql can explicitly query multiple datasets and can implement the 
>> alternativeimdb examples.
> 
> 
> I don't see how you can express recursive (closure) queries in  SPARQL. 

You can't, I wasn't suggesting that, just that the specific example you 
showed (alternativemdb) isn't recursive and you could implement each of the 
example independentmovie and lowbudgetmovie predicates (including the 
scoped expressions) as single SPARQL queries.

> That was mainly what I meant to say here. SPARQL is meant to query fact 
> bases and not interlinked rule bases with intensional, linked and 
> possibly recursive view definitions. 

SPARQL queries a set of RDF models, it doesn't preclude some of those 
models being (lazily or eagerly) generated by some arbitrary process such 
as rule-based deduction.

This seems like an orthogonal issue.

>  Do you have a concrete suggestion how to rephrase this or is it a rule 
> with such closure definition that you miss here and would you have a 
> suggestion for that?

My suggestion would be to just drop the bullet point, it isn't stating a 
new requirement.

[All of this was just a minor aside on the original message.]

Dave
Received on Tuesday, 21 March 2006 18:13:59 GMT

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