$ary_ref  = $dbh->selectall_arrayref($statement);
         $hash_ref = $dbh->selectall_hashref($statement, $key_field);

         $ary_ref  = $dbh->selectcol_arrayref($statement);
         $ary_ref  = $dbh->selectcol_arrayref($statement, \%attr);

         @row_ary  = $dbh->selectrow_array($statement);
         $ary_ref  = $dbh->selectrow_arrayref($statement);
         $hash_ref = $dbh->selectrow_hashref($statement);