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Contents
Preface

Virtuoso Functions Guide

Administration
Aggregate Functions
Array Manipulation
BPEL APIs
Backup
Compression
Cursor
Date & Time Manipulation
Debug
Dictionary Manipulation
Encoding & Decoding
File Manipulation
Free Text
Hashing / Cryptographic
LDAP
Locale
Mail
Miscellaneous
Number
Phrases
RDF data
db.dba.rdf_64bit_upg...
db.dba.rdf_audit_met...
db.dba.rdf_backup_me...
db.dba.rdf_convert_r...
db.dba.rdf_graph_gro...
db.dba.rdf_graph_gro...
db.dba.rdf_langmatch...
db.dba.rdf_load_rdfx...
db.dba.rdf_load_rdfx...
db.dba.rdf_quad_uri
db.dba.rdf_quad_uri_...
db.dba.rdf_quad_uri_...
db.dba.rdf_regex
db.dba.rdf_restore_m...
db.dba.rdf_triples_t...
db.dba.rdf_triples_t...
db.dba.rdf_ttl2hash
db.dba.rdf_void_stor...
db.dba.sparql_eval
db.dba.sparql_eval_t...
db.dba.sparql_rexec
db.dba.sparql_rexec_...
db.dba.sparql_rexec_...
db.dba.ttlp
db.dba.ttlp_mt
db.dba.ttlp_mt_local...
isref
__xml_get_ns_prefix
__xml_get_ns_uri
iri_split
rdfs_rule_set
Remote SQL Data Source
Replication
SOAP
SQL
String
Transaction
Type Mapping
UDDI
User Defined Types & The CLR
Virtuoso Java PL API
Virtuoso Server Extension Interface (VSEI)
Web & Internet
XML
XPATH & XQUERY

Functions Index

IsRef

Returns true if non-blank IRI
IsRef (in iri any);
Description

Returns true if non-blank IRI

Parameters
iri – IRI resource
Return Types

Returns 1 if the IRI is non-blank IRI. Otherwise returns 0.

Examples

SQL>SPARQL
SELECT COUNT(DISTINCT (?o)) 
WHERE 
  { 
    ?s ?p ?o . 
    FILTER ( IsRef(?o)) 
  } 
LIMIT 10

callret-0
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