code: protected function findTableNames($schema = '')
      {
          $pdo = $this->db->getSlavePdo();
          $tables = $pdo->cubrid_schema(\PDO::CUBRID_SCH_TABLE);
          $tableNames = [];
          foreach ($tables as $table) {
              // do not list system tables
              if ($table['TYPE'] != 0) {
                  $tableNames[] = $table['NAME'];
              }
          }
  
          return $tableNames;
      }
docs: {@inheritdoc}