W3C home > Mailing lists > Public > public-rdf-dawg-comments@w3.org > January 2006

Re: major technical: no subqueries [OK?]

From: Dan Connolly <connolly@w3.org>
Date: Wed, 25 Jan 2006 10:18:10 -0600
To: Fred Zemke <fred.zemke@oracle.com>
Cc: public-rdf-dawg-comments@w3.org
Message-Id: <1138205890.4991.549.camel@dirk.w3.org>

On Thu, 2006-01-12 at 17:23 -0600, Dan Connolly wrote:
> On Thu, 2006-01-12 at 13:42 -0800, Fred Zemke wrote:
> [...]
> > This is of course analogous to subqueries and in-line views in SQL. 
> > The originators of SQL mistakenly believed that they did not need
> > subqueries, so subqueries were not part of the original design.
> We didn't identify subqueries as one of our requirements either.
>  http://www.w3.org/TR/rdf-dawg-uc/
> but your request is well-made, complete with use case.
> I have forwarded it to the working group for consideration.

Consideration of your use case did not yeild a critical mass of

Arguments against adding this feature/requirement now included:

We have a number of 
related postponed issues including #cascadedQueries and #countAggregate.  All 
these features would be good so the choice is going with the lesser and 
current v1 with the full expectation that a v2 will be needed, as against 
waiting until all features have been addressed.  I believe we have a design 
that does not exclude the possibility (the syntax being the easier bit).
 -- http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JanMar/0099.html


I see no great obstacles into 
allowing subqueries into SPARQL, but it must be recognized that the 
added implementation burden is significant. To me, the more logical 
route would be to recognize this as a useful feature and to postpone it, 
for now.

I would also like to point out that there are more forms of subquerying 
than are sketched in the user's comments (for example, things like ANY 
and ALL modifiers, or the IN set membership operator) and I feel that if 
we decide to put this on the critical path, we should take a good look 
at all of these. Which is another good reason to postpone for now, IMHO.
 -- http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JanMar/0097.html

I have noted your comment under a relevant postponed issue

I hope you find this response satisfactory; please let us know whether
you do.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Wednesday, 25 January 2006 16:18:19 UTC

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