On 21 Aug 2008, at 16:51, Axel Polleres wrote:
Tackling the question from the more theoretical side,I like non-monotonic SPARQL queries like the ones modeling set difference.E.g."Give me all persons *without* an email address" in a certain FOAF graph.i) It is already folklore, that you can do that with using the ! bound() filter outside an optional, i.e.SELECT ?X FROM G WHERE { ?X a foaf:Person OPTIONAL { ?X foaf:mbox ?M} FILTER (! bound(?X) ) }
Shouldn't that be !bound(?M) ? - Steve
