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Re: Proposal to drop disjunction requirement

From: Kendall Clark <kendall@monkeyfist.com>
Date: Fri, 1 Oct 2004 13:01:44 -0400
To: DAWG public list <public-rdf-dawg@w3.org>
Message-ID: <20041001170144.GA32707@monkeyfist.com>

On Thu, Sep 30, 2004 at 03:45:20PM +0100, Steve Harris wrote:

> Simple algorithm for conveting a disjuntive expression to one expressed on
> optionals: take any common part of each branck of the disjunction, express
> that as the must-bind part, place each of the remaining parts of the
> disunction as an optional subgraph. You may then need to apply some value
> constraints to reduce the set to the answer your interested in. eg:

Okay, but surely the, uh, "smart" thing to do here is for you to treat
syntactic disjunction in this way, i.e., rewrite the query according
to this algorithm before executing it, instead of requiring the Poor
Dumb User (i.e., *me*) to do it?

I think, if we're really worried about learning curve for end users,
that requiring them to learn yr algorithm to more complex queries when
they want to write queries with disjunctions is a bit much. At least,
requiring them to learn to do this is *far more onerous* a burden than
teaching them about an infix operator or using parens to group things
or about precedence rules.

We have 2.13 and 3.13 in UC&R that imply disjunction in SPARQL. I
haven't heard enough to disregard that.

Kendall Clark
Received on Friday, 1 October 2004 17:04:22 UTC

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