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Issue Details [XML]

Key: SES-740
Type: New Feature New Feature
Status: Resolved Resolved
Resolution: Fixed
Priority: Major Major
Assignee: Jeen Broekstra
Reporter: Jeen Broekstra
Votes: 0
Watchers: 0
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Sesame

SPARQL 1.1 Support: MINUS

Created: 20/Jan/11 03:00 AM   Updated: 05/May/11 12:04 AM
Component/s: Query Engine, Query Model, SPARQL
Affects Version/s: None
Fix Version/s: 2.4.0-alpha1, 2.4.0


 Description   
See http://www.w3.org/TR/sparql11-query/#negation

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Comment by Jeen Broekstra [20/Jan/11 04:10 AM]
There's a bit of an issue here as SPARQL's interpretation of MINUS is not precisely the same as Sesame/SeRQL's: Sesame treats a MINUS as a set difference between two groups of statements, whereas SPARQL interprets it as a filter on "compatable" bindings.

Comment by Jeen Broekstra [20/Jan/11 06:02 AM]
checked in a first implementation which works on the assumption that MINUS and NOT EXISTS are exactly the same for cases where there is a shared variable between lhs and rhs. In the case where there is no shared variable, MINUS is a NoOp as it can have no influence on the query result. Pending confirmation/clarification from the DAWG that this is a correct assumption.

Comment by Jeen Broekstra [22/Jan/11 09:23 PM]