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1.5.44.How can I perform search for predicate values?
What?
Creation of a stored procedure that enables users to find properties based on their string based token patterns.
Why?
When working with datasets from disparate datasources in a common named graph, there are times when you seek to scope sparql or spasql queries to specific property IRI/URI patterns without embarking upon inefficient regex heuristics.
What?
Make a stored procedure for querying against the main quad store table (rdf_quad). Surface the procedure as a magic predicate using "bif:" prefix. To find all the properties whose predicates start with "http://www.openlinksw.com/", a Virtuoso/PL procedure can be used as listed below:
SQL> create procedure PREDICATES_OF_IRI_PATH (
in path varchar,
in dump_iri_ids integer := 0)
{
declare PRED_IRI varchar;
declare PRED_IRI_ID IRI_ID;
declare path_head_len integer;
if (dump_iri_ids)
result_names (PRED_IRI_ID);
else
result_names (PRED_IRI);
for ( SELECT RP_NAME, RP_ID
FROM RDF_PREFIX
WHERE (RP_NAME >= path) AND (RP_NAME < path || chr(255)) ) do
{
declare fourbytes varchar;
fourbytes := '----';
fourbytes[0] := bit_shift (RP_ID, -24);
fourbytes[1] := bit_and (bit_shift (RP_ID, -16), 255);
fourbytes[2] := bit_and (bit_shift (RP_ID, -8), 255);
fourbytes[3] := bit_and (RP_ID, 255);
for ( SELECT RI_NAME, RI_ID from RDF_IRI
WHERE (RI_NAME >= fourbytes) AND (RI_NAME < fourbytes || chr(255)) ) do
{
if (exists (SELECT TOP 1 1 FROM RDF_QUAD WHERE P=RI_ID))
result (case when (dump_iri_ids) then RI_ID else RP_NAME || subseq (RI_NAME, 4) end);
}
}
for ( path_head_len := length (path)-1; path_head_len >= 0; path_head_len := path_head_len - 1)
{
for ( SELECT RP_NAME, RP_ID from RDF_PREFIX
WHERE RP_NAME = subseq (path, 0, path_head_len) ) do
{
declare fourbytes varchar;
fourbytes := '----';
fourbytes[0] := bit_shift (RP_ID, -24);
fourbytes[1] := bit_and (bit_shift (RP_ID, -16), 255);
fourbytes[2] := bit_and (bit_shift (RP_ID, -8), 255);
fourbytes[3] := bit_and (RP_ID, 255);
for ( SELECT RI_NAME, RI_ID from RDF_IRI
WHERE (RI_NAME >= fourbytes || subseq (path, path_head_len))
AND (RI_NAME < fourbytes || subseq (path, path_head_len) || chr(255)) ) do
{
if (exists (SELECT TOP 1 1 FROM RDF_QUAD WHERE P=RI_ID))
result (case when (dump_iri_ids) then RI_ID else RP_NAME || subseq (RI_NAME, 4) end);
}
}
}
}
;
Done. -- 16 msec.
Example Usage
-
Execute:
set echo on;
-
Collect all predicates that start with:
-- http://www.openlinksw.com/ SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/', 1); VARCHAR _______________________________________________________________________________ #i351 #i159 #i10 #i8 ... -- http://www.openlinksw.com/schemas/virtrdf SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf', 1); PRED_IRI_ID VARCHAR _______________________________________________________________________________ #i159 #i10 #i8 #i6 #i160 #i269 #i278 #i275 -- http://www.openlinksw.com/schemas/virtrdf# SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf#',1); PRED_IRI_ID VARCHAR _______________________________________________________________________________ #i159 #i10 #i8 #i6 #i160 #i269 #i278 ... -- http://www.openlinksw.com/schemas/virtrdf#i SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf#i',1); PRED_IRI_ID VARCHAR _______________________________________________________________________________ #i159 #i10 #i8 -- other SQL>PREDICATES_OF_IRI_PATH ('no://such :)', 1); 0 Rows. -- 0 msec. -
Show all predicates that start with:
-- http://www.openlinksw.com/ SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/'); PRED_IRI VARCHAR _______________________________________________________________________________ http://www.openlinksw.com/schemas/DAV#ownerUser http://www.openlinksw.com/schemas/virtrdf#inheritFrom http://www.openlinksw.com/schemas/virtrdf#isSpecialPredicate http://www.openlinksw.com/schemas/virtrdf#item http://www.openlinksw.com/schemas/virtrdf#loadAs http://www.openlinksw.com/schemas/virtrdf#noInherit http://www.openlinksw.com/schemas/virtrdf#qmGraphMap http://www.openlinksw.com/schemas/virtrdf#qmMatchingFlags http://www.openlinksw.com/schemas/virtrdf#qmObjectMap http://www.openlinksw.com/schemas/virtrdf#qmPredicateMap http://www.openlinksw.com/schemas/virtrdf#qmSubjectMap ... -- http://www.openlinksw.com/schemas/virtrdf SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf'); PRED_IRI VARCHAR _______________________________________________________________________________ http://www.openlinksw.com/schemas/virtrdf#inheritFrom http://www.openlinksw.com/schemas/virtrdf#isSpecialPredicate http://www.openlinksw.com/schemas/virtrdf#item http://www.openlinksw.com/schemas/virtrdf#loadAs http://www.openlinksw.com/schemas/virtrdf#noInherit http://www.openlinksw.com/schemas/virtrdf#qmGraphMap http://www.openlinksw.com/schemas/virtrdf#qmMatchingFlags http://www.openlinksw.com/schemas/virtrdf#qmObjectMap http://www.openlinksw.com/schemas/virtrdf#qmPredicateMap http://www.openlinksw.com/schemas/virtrdf#qmSubjectMap http://www.openlinksw.com/schemas/virtrdf#qmTableName ... -- http://www.openlinksw.com/schemas/virtrdf# SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf#'); PRED_IRI VARCHAR _______________________________________________________________________________ http://www.openlinksw.com/schemas/virtrdf#inheritFrom http://www.openlinksw.com/schemas/virtrdf#isSpecialPredicate http://www.openlinksw.com/schemas/virtrdf#item http://www.openlinksw.com/schemas/virtrdf#loadAs http://www.openlinksw.com/schemas/virtrdf#noInherit http://www.openlinksw.com/schemas/virtrdf#qmGraphMap http://www.openlinksw.com/schemas/virtrdf#qmMatchingFlags http://www.openlinksw.com/schemas/virtrdf#qmObjectMap http://www.openlinksw.com/schemas/virtrdf#qmPredicateMap http://www.openlinksw.com/schemas/virtrdf#qmSubjectMap http://www.openlinksw.com/schemas/virtrdf#qmTableName http://www.openlinksw.com/schemas/virtrdf#qmf01blankOfShortTmpl http://www.openlinksw.com/schemas/virtrdf#qmf01uriOfShortTmpl http://www.openlinksw.com/schemas/virtrdf#qmfBoolOfShortTmpl http://www.openlinksw.com/schemas/virtrdf#qmfBoolTmpl ... -- http://www.openlinksw.com/schemas/virtrdf#i SQL>PREDICATES_OF_IRI_PATH ('http://www.openlinksw.com/schemas/virtrdf#i'); PRED_IRI VARCHAR _______________________________________________________________________________ http://www.openlinksw.com/schemas/virtrdf#inheritFrom http://www.openlinksw.com/schemas/virtrdf#isSpecialPredicate http://www.openlinksw.com/schemas/virtrdf#item 3 Rows. -- 15 msec. -- other SQL>PREDICATES_OF_IRI_PATH ('no://such :)'); PRED_IRI VARCHAR _______________________________________________________________________________ 0 Rows. -- 15 msec.
If you want to use the procedure's output inside SPARQL queries, it can be wrapped by a procedure view and it in turn can be used in an Linked Data View but it is redundant for most applications.
For typical "almost static" data, it is more practical to write a procedure that will store all found predicates in some dedicated "dictionary" graph and then use the graph as usual.