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.

How?

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.

Note: 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.

Virtuoso Tips and Tricks Collection

Virtuoso Open-Source Edition

How can I perform search for predicate values?

What?

Why?

How?

Example Usage

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