docs: void initialize()
      {
          if (m_backend == BackendTarget.HSQLDB_BACKEND) {
              m_non_voltdb_backend = HsqlBackend.initializeHSQLBackend(m_siteId,
                                                         m_context);
          }
          else if (m_backend == BackendTarget.POSTGRESQL_BACKEND) {
              m_non_voltdb_backend = PostgreSQLBackend.initializePostgreSQLBackend(m_context);
          }
          else if (m_backend == BackendTarget.POSTGIS_BACKEND) {
              m_non_voltdb_backend = PostGISBackend.initializePostGISBackend(m_context);
          }
          else {
              m_non_voltdb_backend = null;
          }
      }