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Re: Negation decision : unexpected effects

From: Steve Harris <steve.harris@garlik.com>
Date: Mon, 5 Apr 2010 22:16:58 +0100
Cc: Andy Seaborne <andy.seaborne@talis.com>, SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <37A3D752-D02B-4DDF-8994-929D4ED2C512@garlik.com>
To: Lee Feigenbaum <lee@thefigtrees.net>
On 2010-04-05, at 21:51, Lee Feigenbaum wrote:
>>> 
>>> I wouldn't be in favor of this proposal - I'd find it very difficult to
>>> justify adding 2 forms of negation to SPARQL that seem virtually
>>> indistinguishable from one another in most scenarios.
>> 
>> We are doing that under the F2F3 resolution (the second one) regardless
>> of my proposal and under the first proposal of the F2F, negation used
>> the syntax "NOT EXISTS".
> 
> I believe that most of the user world would simply accept that the words used for negation as a graph pattern and negation in a filter are different. I don't think any such easy explanation can be given when both can be used as graph pattern keywords.

Indeed, SQL has the MINUS table operation, and NOT EXISTS in the WHERE/FILTER operation as well.

- Steve

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Received on Monday, 5 April 2010 21:17:27 GMT

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