Function: DB.DBA.SPARQL_REXEC - Virtuoso Functions Guide

DB.DBA.SPARQL_REXEC

Remote execution of SPARQL via SPARQL protocol, produces a result set of SQL values.

DB.DBA.SPARQL_REXEC (in service varchar, in query varchar, in dflt_graph varchar, in named_graphs any, in req_hdr any, in maxrows integer, in bnode_dict any);

Description

Remote execution of SPARQL via SPARQL protocol, produces a result set of SQL values.

Parameters

service – service URI to call via HTTP.

query – text of SPARQL query to execute.

dflt_graph – default graph IRI, if not NULL then this overrides what is specified in query

named_graphs – vector of named graph IRIs, if not NULL then this overrides what is specified in query

req_hdr – additional HTTP header lines that should be passed to the service; 'Host: ...' is most popular.

maxrows – limit on numbers of rows that should be returned.

bnode_dict – dictionary of bnode ID references.

Return Types

any

Examples

create procedure SPARQL_TEST (in rquri varchar, in graph_uri varchar, in resuri varchar, in in_result integer := 0)
{
  declare REPORT varchar;
  declare rqtext, sqltext varchar;
  declare app_env any;
  declare rset, row any;
  declare etalon_vars, etalon_rowids, etalon_rows any;
  declare rctr, rcount integer;
  declare copyright_filter any;
  if (not in_result)
    result_names (REPORT);
  result ('');
  declare exit handler for sqlstate '*' {
   ...
    };
  ...
  rqtext := replace (cast (XML_URI_GET ('', rquri) as varchar), '# \044Id:', '# Id:');
      declare rexec_stat, rexec_msg varchar;
      declare bnode_dict, rexec_rmeta, rexec_rrows any;
      rexec_stat := '00000';
      rexec_msg := 'OK';
      bnode_dict := dict_new ();
      rexec_rrows := null;
      exec (
        'DB.DBA.SPARQL_REXEC (?, ?, ?, ?, ?, ?, ?)',
	rexec_stat, rexec_msg,
	vector (
	  WB_CFG_HTTP_URI() || '/sparql/',
	  rqtext,
	  graph_uri,
	  vector (),
	  '',
	  10000,
	  bnode_dict ),
	10000, rexec_rmeta, rexec_rrows );
      if (not isarray (rexec_rrows))
        rexec_rrows := null;
      result (sprintf ('Remote exec of %s', rquri));
      dump_large_text_impl (
        sprintf ('  completed with state %s msg %s and %d rows',
        rexec_stat, rexec_msg, length (rexec_rrows) ) );
  result ('PASSED');
};

22. Virtuoso Functions Guide - DB.DBA.SPARQL_REXEC

DB.DBA.SPARQL_REXEC