Thanks, Andy! S.
On 4/25/17, 3:34 AM, "Andy Seaborne" <[email protected]> wrote: The Jena users list is at [email protected]. > CONSTRUCT { > ?s ?p0 ?o0 . > ?o0 ?p1 ?o1 . > ?o1 ?p2 ?o2 . > ?o2 ?p3 ?o3 . > ?o3 ?p4 ?o4 . > } WHERE > { > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?s ?p0 ?o0 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o0 ?p1 ?o1 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o1 ?p2 ?o2 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o2 ?p3 ?o3 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o3 ?p4 ?o4 }} Consider what happens if { ?s ?p0 ?o0 } matches, then { ?o0 ?p1 ?o1 } does not. { ?o1 ?p2 ?o2 } is not attached to ?s via ?o1 so it matches the whole graph. Your description would be better written as: GRAPH <http://ao.com/namedGraph/g> { ?s ?p0 ?o0 OPTIONAL { ?o0 ?p1 ?o1 OPTIONAL { ?o1 ?p2 ?o2 OPTIONAL { ?o2 ?p3 ?o3 OPTIONAL { ?o3 ?p4 ?o4 } }}} } Andy On 25/04/17 04:02, Dimov, Stefan wrote: > … on the other hand, DESCRIBE works correctly ☺: > > DESCRIBE ?s > { > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?s ?p0 ?o0 }} You don't need the rest - only ?s matters in the DESCRIBE > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o0 ?p1 ?o1 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o1 ?p2 ?o2 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o2 ?p3 ?o3 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o3 ?p4 ?o4 }} > > FILTER (STR(?s) = "http://ao.com/uc/example";) > } > > It returns only the object specified by the filter. > > Correct me if I’m wrong, but seems there’s a bug in the CONSTRUCT implementation … > > S. > > From: Stefan Dimov <[email protected]> > Date: Monday, April 24, 2017 at 7:45 PM > To: "[email protected]" <[email protected]> > Subject: Unexpected SPARQL CONSTRUCT output > > I have in my named graph only two json-ld objects – “example” and example1”. > I have this query (filter is ‘example1’): > > CONSTRUCT { > ?s ?p0 ?o0 . > ?o0 ?p1 ?o1 . > ?o1 ?p2 ?o2 . > ?o2 ?p3 ?o3 . > ?o3 ?p4 ?o4 . > } WHERE > { > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?s ?p0 ?o0 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o0 ?p1 ?o1 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o1 ?p2 ?o2 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o2 ?p3 ?o3 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o3 ?p4 ?o4 }} > > FILTER (STR(?s) = "http://ao.com/uc/example1";) > } > > and it returns me both ‘example’ and ‘example1’: > > <http://ao.com/uc/example1> > <http://ao.com/propOf> [ <http://ao.com/object> "w4" ; > <http://ao.com/property> [ <http://ao.com/g/term> > [ <http://ao.com/order#0> "w0" ; > <http://ao.com/order#1> "w1" ; > <http://ao.com/order#2> "w2" ; > <http://ao.com/order#3> "w3" > ] ] > ] . > > <http://ao.com/uc/example> > <http://ao.com/propOf> [ <http://ao.com/object> "w5" ; > <http://ao.com/property> [ <http://ao.com/g/term> > [ <http://ao.com/order#0> " w0" ; > <http://ao.com/order#1> "w1" ; > <http://ao.com/order#2> "w" ; > <http://ao.com/order#3> "w4" > ] ] > ] . > > not just “example1” as one would expect. > > If I change the filter to “example”, again I get both ‘example’ and ‘example1’. > > If I change the filter to something else (i.e. – non-existent), I get an empty result. That means, the filter works, but not quite as expected. > > More interesting – if I reduce the depth of the query: > > CONSTRUCT { > ?s ?p0 ?o0 . > ?o0 ?p1 ?o1 . > ?o1 ?p2 ?o2 . > } WHERE > { > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?s ?p0 ?o0 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o0 ?p1 ?o1 }} > OPTIONAL { GRAPH <http://ao.com/namedGraph/g> { ?o1 ?p2 ?o2 }} > > FILTER (STR(?s) = "http://ao.com/uc/example";) > } > > it returns me (exactly as expected) only the object that matches the filter: > > <http://ao.com/uc/example1> > <http://ao.com/propOf> [ <http://ao.com/object> "w4" ; > <http://ao.com/property> [ <http://ao.com/g/term> > [] ] > ] . > > Why is that? Is there any way to work around this? > > Stefan > > > > > > >
