This is useful for reproducing a database with an unknown schema into a hash of a hash of an array.
my $sqlstr1 ="select table_name, column_name".
                    " from Dba_tab_columns".
                    " where owner = '$schema'".
                    " order by table_name, column_name";
        my $sth=$db->prepare($sqlstr1) or print STDOUT "Query:GetData 
+Failed";
        $sth->execute;
        my $table_column = $sth->fetchall_arrayref;
        $sth->finish;
        
        for $table_column_r (@{$table_column})
        {
             if ($table_column_r->[0] eq "EMP")
            {
                 my $sqlstr2 =" select $table_column_r->[1]".
                            " from $schema.$table_column_r->[0]";
                my $sth=$db->prepare($sqlstr2) or print STDOUT "Query:
+GetTablesColumnsData Failed";
                $sth->execute;
                warn print STDOUT "\n***Error*** Table: $table_column_
+r->[0]  Column: $table_column_r->[1]      \n", $sth->errstr(), "\n"
                     if $sth->err();
                warn print SUMMARY "\n***Error*** Table: $table_column
+_r->[0]  Column: $table_column_r->[1]      \n", $sth->errstr(), "\n"
                     if $sth->err();
                my $column_data = $sth->fetchall_arrayref;
                $sth->finish;
                
                # This for-loop create a hash of a hash of an array wi
+th the keys {table name} and {column name}
                for $row (@{$column_data})
                {
                    push (@{$tables{$table_column_r->[0]}{$table_colum
+n_r->[1]}}, $row->[0]);
                    # To print value of hash: p @{$tables{$table_colum
+n_r->[0]}{$table_column_r->[1]}}
                }
                undef @data_array;
            }
        }

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In reply to Database Table to Hash of Hash of Array by timo

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