I am afraid I had data in this format and by mistake now I have loaded the data in this format...and it took TDB 10 days to load it on a server with 64GB RAM. Is there some way by which I may still query it on relative IRIs? (I am asking because I have to report the results today and my boss will get hyper angry on me).
If there is some way out then please let me know? On Fri, Dec 27, 2013 at 6:35 AM, Damian Steer <[email protected]> wrote: > > On 26 Dec 2013, at 20:51, Rose Beck <[email protected]> wrote: > > > I created my data file containing the following data(try.nq): > > > > <http://dbpedia.org/data/Plasmodium_hegneri.xml> < > > http://code.google.com/p/ldspider/ns#headerInfo> > > _:header16125770191335188966549 <a> . > > Ah, here is the issue. > > N-Quads _doesn't_ permit relative URIs / IRIs. [1] TDB is being kind / > unhelpful and loading the data as requested, full of relative IRIs. > This is, strictly, broken RDF. The behaviour when you work on it is as a > consequence undefined. > > (If you run the data through validation this issue is apparent: > > $ riot --validate try.nq > ERROR [line: 1, col: 133] Relative IRI: a > ...) > > > Then I fired the following SPARQL command: > > root@server:/home/apache-jena-2.10.0/bin# ./tdbquery --time > > ... > > > I got the following output: > > ----------------- > > | a | b | c | > > ================= > > | <a> | <b> | > > The answer is a) correct but b) very unhelpful. These are relative IRIs > but no base is given. > > > After this I tried another SPARQL query(given below) for which I obtained > > an incorrect output: > > SPARQL query: > > root@server:/home/apache-jena-2.10.0/bin# ./tdbquery --time > > --loc=/home/Jena/try "select ?a?b?c where{ graph ?j1{?a <b> < > > http://dbpedia.org/data/Plasmodium_hegneri.xml>} }" > > Output: > > ------------- > > | a | b | c | > > ============= > > ------------- > > Time: 0.095 sec > > SPARQL, unlike N-Quads, allows relative IRIs. In the absence of a BASE > directive the IRIs are resolved relative to the query itself. In this case > the current directory is used as the base, so <b> is understood as > <CURRENT_DIR/b>. You can see this if you add --explain: > > $ tdbquery --explain --loc=try "select ?a?b?c where{ graph ?j1{?a <b> < > http://dbpedia.org/data/Plasmodium_hegneri.xml>} }" > 00:58:24 INFO exec :: QUERY > SELECT ?a ?b ?c > WHERE > { GRAPH ?j1 > { ?a <b> <http://dbpedia.org/data/Plasmodium_hegneri.xml> } > } > 00:58:24 INFO exec :: ALGEBRA > (project (?a ?b ?c) > (quadpattern (quad ?j1 ?a <file:///private/tmp/b> < > http://dbpedia.org/data/Plasmodium_hegneri.xml>))) > 00:58:24 INFO exec :: Execute :: (?j1 ?a > <file:///private/tmp/b> <http://dbpedia.org/data/Plasmodium_hegneri.xml>) > ------------- > | a | b | c | > ============= > ------------- > > <b> is resolved to <file:///private/tmp/b> (I ran this in the temp dir). > Thus no results. > > So the short answer is that the input data is broken. > > Damian > > [1] <http://www.w3.org/TR/n-quads/#sec-iri> > [2] <http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#relIRIs>
