Connecting directly to virtuoso

via isql

List of tables

is a relational database and what not

All the tables in Virtuoso start with the DB.DBA. prefix.

RDF_QUAD -- The main table which contains all the statements. It contains four rows "S", "P", "O" and "G" for the subject, predicate, object and graph.

The sparql_to_sql_text() function can be used to convert a SPARQL query directly to the SQL it would be executed as.

varchar sparql_to_sql_text
( in squery varchar );

It's very useful in debugging why many sparql queries are taking so long.