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Re: Working Draft feedback items

From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Date: Mon, 7 Mar 2005 14:25:01 +0000
To: "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>
Message-ID: <20050307142501.GG3692@login.ecs.soton.ac.uk>

On Sun, Mar 06, 2005 at 04:58:16 +0000, Andy Seaborne wrote:
> == 4 == Syntactic support for reification
> 
> Some people use reification and use it a lot - some people use named
> graph-like approaches and avoid reification - most people just don't use 
> either.

The others seem good, and I have no opinion on this...
 
> == 5 == Sorting/Grouping
> 
> A request for SQL-like facilities to control the presentation of result
> sets.  It makes testing interesting - sometimes unordered is acceptable and
> sometimes it's (partially) not.
> 
> There are issues around defining the ordering between unrelated things like 
> strings and URIs, bNodes and integers, dates and doubles - would need some 
> arbitrary decisions.  Not clear to me that it could be pushed into SQL 
> sorting for the semi-structued cases - in SQL, the engine knows the column 
> type.

I think we allready discussed this and decided it was too much work to
specify at this stage. I have uses for sorting, though I'm not sure any of
my users do, so leaving it for now is fine by me. I dont think theres
consensus on how it should work.
 
> The decision would seem to be as much WG time as anything else.  I suppose 
> that we could reserve syntax without defining semantics in tests at this 
> stage but that isn't very helpful to interoperability/

Its not worked very well for SQL.
 
> == 6 == Optionals and order dependencies.
> 
> The alternatives I think if or know about are (briefly):
> 
>   A/ An order rule that states variables must be used in fixed
>      patterns before optionals if possible.  We can either make
>      a query that does not do this illegal, execute in this
>      canonical order or leave to implementations.

I have a preference for this. Currently I process all the non-OPTIONAL
blocks, then all the optionals in order, so I have a preference for doing
that :)

- Steve 
Received on Monday, 7 March 2005 14:45:54 GMT

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