/**
  * Calls underlying db to check if table exists. Always returns
  * true if options check_table_exists is set to false
  * @param string $table
  * @return boolean
  */
 protected function _tableExists($table)
 {
     // if no checking of table existence
     if (!$this->check_table_exists) {
         // always assume table exists
         return true;
     }
     return $this->db->tableExists($table);
 }