Virtuoso RDF Graph Dump based on Inference Rule Utility The graph_dump procedure below can be used to export triples from Named RDF Graphs in N3 triple format to file, filtering based on the specified Inference rule and predicate/property URI: Params: in srcgraph varchar - source graph in format varchar - output format N3 is supported for now in inf varchar - inference name in pred varchar - predicate to filter in out_file varchar - output file prefix in file_length_limit := 1000000000 - maximum size of files data is dumped in create procedure graph_dump (in srcgraph varchar, in format varchar := 'N3', in inf varchar := null, in pred varchar := null, in out_file varchar, in file_length_limit integer := 1000000000) { declare qr, file_name varchar; declare env, ses, meta, data, h any; declare ses_len, max_ses_len, file_len, file_idx integer; set isolation = 'uncommitted'; max_ses_len := 10000000; file_len := 0; file_idx := 1; if (format <> 'N3') signal ('22023', 'The output format is not supported'); file_name := sprintf ('%s%06d.ttl', out_file, file_idx); string_to_file (file_name || '.graph', srcgraph, -2); string_to_file (file_name, sprintf ('# Dump of graph <%s>, as of %s\n', srcgraph, cast (now() as varchar)), -2); --env := vector (dict_new (16000), 0, '', '', '', 0, 0); env := vector (dict_new (16000), 0, '', '', '', 0, 0, 0, 0); ses := string_output (); if (inf is not null) inf := sprintf ('define input:inference "%s"', inf); else inf := ''; if (pred is not null) pred := sprintf ('<%s>', pred); else pred := '?p'; qr := sprintf ('select * from (sparql define input:storage "" %s select ?s %s as ?p ?o { graph <%S> { ?s %s ?o } } ) as sub option (loop)', inf, pred, srcgraph, pred); exec (qr, null, null, vector (), 0, null, null, h); while (0 = exec_next (h, null, null, data)) { declare "s", "p", "o" any; "s" := data[0]; "p" := data[1]; "o" := data[2]; http_ttl_triple (env, "s", "p", "o", ses); ses_len := length (ses); if (ses_len > max_ses_len) { file_len := file_len + ses_len; if (file_len > file_length_limit) { http (' .\n', ses); string_to_file (file_name, ses, -1); file_len := 0; file_idx := file_idx + 1; file_name := sprintf ('%s%06d.ttl', out_file, file_idx); string_to_file (file_name, sprintf ('# Dump of graph <%s>, as of %s (part %d)\n', srcgraph, cast (now() as varchar), file_idx), -2); env := vector (dict_new (16000), 0, '', '', '', 0, 0); } else string_to_file (file_name, ses, -1); ses := string_output (); } } exec_close (h); if (length (ses)) { http (' .\n', ses); string_to_file (file_name, ses, -1); } } ; Example SUMO ontology was recently mapped to DBpedia by its creators using RDF/XML and loaded into the DBpedia SPARQL Endpoint. Issues:To add to DBpedia data sets, N3 is preferred format. Cross Links needed i.e. mapping <#dbpediaURI> owl:sameAs <#SumoURI> in addition to the authors links which are solely, <#SumoURI> owl:sameAs <#DBpediaURI> Solution:Make an inference rules graph where owl:sameAs is explicitly asserted to be an owl:SymmetricalProperty type. ttlp('owl:sameAs a owl:SymmetricalProperty .', '', 'rule_graph'); Make a Named Rule that's associated the the Named Graph in step above. rdfs_rule_set ('sas', 'rule_graph'); Run the graph_dump export procedure with the inference rule parameter and predicate/property filter option to export the data to file, in N3 format and with necessary UNKNOWN tag: http://www.w3.org/1999/xhtml:nowikiowl:sameas cross links. graph_dump ('http://www.ontologyportal.org/SUMO#', 'N3', 'sas', 'http://www.w3.org/2002/07/owl#sameAs', 'sumo_');