VirtSetPrefixNamesSet Standard Prefix Names for common vocabulariesSet Standard Prefix Names for common vocabularies In order to set standard prefix names for common vocabularies on dumps to either .n3 or .ttl, you should use the xml_set_ns_decl Virtuoso function. The initial list of namespace declarations can be found by executing from iSQL or Conductor UI: SQL> SELECT * FROM DB.DBA.SYS_XML_PERSISTENT_NS_DECL; Example Load the ontology, for ex.: SQL> DB.DBA.RDF_LOAD_RDFXML (http_get(''), '', ''); Done. -- 109 msec. Check total triples retrieved: SQL>SPARQL SELECT COUNT(*) from <> WHERE {?s ?p ?o}; callret-0 INTEGER _______________________________________________________________________________ 495 1 Rows. -- 16 msec. Register the XML NS prefix: SQL>DB.DBA.XML_SET_NS_DECL ('txn', '', 2); Done. -- 0 msec. Use the prefix, for ex. executing: SQL>SPARQL SELECT COUNT(*) WHERE { ?s ?p txn:SpeciesConcept }; callret-0 INTEGER _______________________________________________________________________________ 25 1 Rows. -- 0 msec.