public function setDbName( ?string $dbName ) : PgSQL
   {

      if ( ! $this->_supportedAttributes->get( 'dbname' )->validateValue( $dbName ) )
      {
         throw new ArgumentException( 'dbname', $dbName, 'Invalid database name!' );
      }

      $this->_attributes[ 'dbname' ] = $dbName;

      return $this;

   }