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Re: RDQL functionality vs. DAWG requirements

From: Eric Prud'hommeaux <eric@w3.org>
Date: Tue, 29 Jun 2004 06:55:01 -0400
To: public-rdf-dawg@w3.org
Message-ID: <20040629105501.GD20261@w3.org>
On Tue, Jun 01, 2004 at 11:23:51PM +0900, Eric Prud'hommeaux wrote:
> 
> Persuant to my action item to review RDQL with respect to the
> requirements [1] from the 25-May 2004 teleconference [2], I evaluated
> (and implemented) RDQL per the Jan 2004 W3C submission [3].
> 
> I was planning on getting this out later this week, but earlier is
> probably better than better. Besides, Andy will fix it all up for me.
> 
> I copped Bryan's convention [4] for reporting requirement support:
> 
>      rdql+ : rdql supports this requirement today under a suitable
>  	     protocol binding and/or query language.
> 
>      rdql- : the requirement appears to be explicitly outside of the
> 	     scope of rdql, which is not to say that it could NOT be
> 	     met by a suitable revision of rdql.
> 
>      rdql? : need more information to make the determination.
> 
> This somewhat contrived example query will serve as a syntactic
> example of how RDQL meets the requirements:
> 
>   SELECT ?family , ?given
>   FROM   <http://example.org/JohnzVcard.rdf>
>   WHERE  (?vcard  vcard:FN "John Smith")
>          (?vcard  vcard:N  ?name)
>          (?name   vcard:Family  ?family)
>          (?name   vcard:Given  ?given)
>          (?name   vcard:age  ?age)
>          (?name   vcard:shoeSize  ?shoeSize)
>   AND    ?shoeSize > 5
>   AND    ?age >= ?shoeSize
>   USING  vcard FOR <http://www.w3.org/2001/vcard-rdf/3.0#>
> 
> Requirements:
> 
> rdql+ : 3.1 RDF Graph Pattern Matching
>   WHERE  (?vcard  vcard:FN "John Smith")
>          (?vcard  vcard:N  ?name)
>          (?name   vcard:Family  ?family)
>          (?name   vcard:Given  ?given)
> 
> rdql+ : 3.2 Variable Binding Results 
>   SELECT ?family , ?given
>   From the spec: [[
> The variable "?x" will be bound to the label of the subject resource.
> All such "x" are returned
> ]]
> 
> rdql- : 3.3 Extensible Value Testing
>   Has support for equality and comparison operators for integers.

Oops, seems likely that STR_MATCH and STR_NMATCH provide regexp
support:

StringEqualityExpression
 ::=  	ArithmeticCondition ( 
    <STR_EQ> ArithmeticCondition 
  | <STR_NE> ArithmeticCondition 
  | <STR_MATCH> PatternLiteral 
  | <STR_NMATCH> PatternLiteral )*


> rdql- : 3.4 Subgraph Results
> 
> rdql+ : 3.5 Local Queries
>   The specification does not describe the result format or mechanism,
>   however, an API implementation of this protocol would be able to
>   perform local queries.
> 
> rdql- : 3.6 Optional Match
> 
> rdql+ : 3.7 Limited Datatype Support
>   AND    ?shoeSize > 5
>   AND    ?age >= ?shoeSize
> 
> rdql- : 3.8 Bookmarkable Queries
>   RDQL does not spcify a canonicalization into a local part of a URI.
> 
> rdql+.5 : 3.9 Bandwidth-efficient Protocol
>   Query protocol is terse and easy on the eyes. No result protocol is
>   defined.
> 
> rdql- : 3.10 Result Limits
> 
> Design Objectives:
> 
> rdql+ : 4.1 Human-friendly Syntax
>   RDQL queries read like a sentence. They allow the use of
>   qnames. Term-enclosing parens could be replaced by a single
>   delimiter ala N3, but I it is, in my opinion, easy on the eyes.
> 
> rdql- : 4.2 Provenance
> 
> rdql- : 4.3 Non-existent Triples
> 
> rdql- : 4.4 User-specifiable Serialization
>   RDQL does not specify results format/protocol nor provide syntax to
>   select such.
> 
> rdql- : 4.6 Aggregate Query

I believe I mis-remembered what this requirement was about. At some
point, during face to face one, we discussed aggregating the subgraph
of supporting statements from each result. That is NOT what Aggregate
Query is about. I suspect there's a wording problem in Aggregate
Query (separate mail), but think that RDQL does support it.

> rdql- : 4.6 Additional Semantic Information
> 
> 
> [1] http://www.w3.org/2001/sw/DataAccess/UseCases
> [2] http://www.w3.org/mid/--lost-my-copy-of-the-minutes
> [3] http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/
> [4] http://www.w3.org/mid/D24D16A6707B0A4B9EF084299CE99B39053F8C01@mcl-its-exs02.mail.saic.com
> -- 
> -eric
> 
> office: +1.617.258.5741 NE43-344, MIT, Cambridge, MA 02144 USA
> cell:   +1.857.222.5741
> 
> (eric@w3.org)
> Feel free to forward this message to any list for any purpose other than
> email address distribution.

-- 
-eric

office: +81.466.49.1170 W3C, Keio Research Institute at SFC,
                        Shonan Fujisawa Campus, Keio University,
                        5322 Endo, Fujisawa, Kanagawa 252-8520
                        JAPAN
        +1.617.258.5741 NE43-344, MIT, Cambridge, MA 02144 USA
cell:   +1.857.222.5741 (does not work in Asia)

(eric@w3.org)
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Received on Tuesday, 29 June 2004 06:55:01 GMT

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