1.19 Enhanced RDF ORDER BY Query Processing

Effective with Oracle Database Release 12.2, queries on RDF data that use SPARQL ORDER BY semantics are processed more efficiently than in previous releases.

This internal efficiency involves the use of the ORDER_TYPE, ORDER_NUM, and ORDER_DATE columns in the RDF_VALUE$ metadata table (documented in Statements). The values for these three columns are populated during loading, and this enables ORDER BY queries to reduce internal function calls and to execute faster.

Effective with Oracle Database Release 12.2, the procedure SEM_APIS.ADD_DATATYPE_INDEX creates an index on the ORDER_NUM column for numeric types (xsd:float, xsd:double, and xsd:decimal and all of its subtypes) and an index on ORDER_DATE column for date-related types (xsd:date, xsd:time, and xsd:dateTime) instead of a function-based index as in previous versions. If you want to continue using a function-based index for these data types, you should use the FUNCTION=T option of the SEM_APIS.ADD_DATATYPE_INDEX procedure. For example (assuming a schema-private RDF network named NET1 owned by a database user named RDFUSER):

EXECUTE sem_apis.add_datatype_index('http://www.w3.org/2001/XMLSchema#decimal', options=>'FUNCTION=T', network_owner=>'RDFUSER', network_name=>'NET1');

EXECUTE sem_apis.add_datatype_index('http://www.w3.org/2001/XMLSchema#date', options=>'FUNCTION=T', network_owner=>'RDFUSER', network_name=>'NET1');