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RE: More on MINUS vs. UNSAID

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Wed, 8 Jul 2009 18:15:03 +0000
To: Eric Prud'hommeaux <eric@w3.org>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-ID: <B6CF1054FDC8B845BF93A6645D19BEA3646F2BC062@GVW1118EXC.americas.hpqcorp.net>


> -----Original Message-----
> From: public-rdf-dawg-request@w3.org [mailto:public-rdf-dawg-request@w3.org]
> On Behalf Of Eric Prud'hommeaux
> Sent: 08 July 2009 17:59
> To: Lee Feigenbaum
> Cc: SPARQL Working Group
> Subject: Re: More on MINUS vs. UNSAID
> 


> More specifically, I support conceptual compatibility with SQL MINUS
> modulo adapting it to SPARQL's preservation of cardinality and the
> fact that in SPARQL, you can have no common variables in A and B.
> Your MINUS-AntiJoin+Restriction choice is thus more applicable.

Eric,

What is the cardinality of this MINUS?  I'm not sure what you have in mind.

SPARQL-UNION is not multiset UNION (that has a cardinality function of max, SPARQL's is plus).

Here is some test case data:

LHS:

?a="a" ?b="b"
?a="a" ?b="b"
?a="a"
?a="a"

RHS-1:
?a="a" ?b="b"

RHS-2:
?a="a" ?b="b"
?a="a" ?b="b"

RHS-3:
?a="a" ?b="b"
?b="b"

What are the output tables in each case?

	Andy

Received on Wednesday, 8 July 2009 18:15:12 GMT

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