#!/usr/bin/perl

use strict;
use warnings;
use DBI;

my $count = 0;
my $cfmt; #field format/alignment
my @harr; #array to store hypens
my %hash1; #hash to store fieldnumber <-> fieldtypename pairs
my %hash2; #hash to store fieldnumber <-> fieldlength pairs

my $dbh = DBI->connect("dbi:Oracle://orasrv1:1521/orcl",'scott','tiger');

    my $SQL = "SELECT * FROM EMP";
        my $sth = $dbh->prepare($SQL);

        $sth->execute;

    my $nof = $sth->{NUM_OF_FIELDS};

    for ( my $i = 0; $i < $nof; $i++ ) {
        my $name = $sth->{NAME}[$i];
        my $type = $sth->{TYPE}[$i];
        my $tn=$dbh->type_info($type)->{TYPE_NAME};
        my $prec = $sth->{PRECISION}[$i];

# special treatment for field type DATE, because it returns no field length
    if ($tn eq "DATE") {
        $prec = 10;
    } else {
        $prec = length($name) if (length($name) > $prec);
    }

    $hash1{"$i"} = "$tn";
    $hash2{"$i"} = "$prec";

    # print header, all column names left aligned
        $cfmt = "%-".$prec."s";
        printf("$cfmt ", $name);
        push @harr, '-'x$prec;
    }
    print "\n";

    # print line with hypens under the header
    print join(" ", @harr) . "\n";

 while ( my @row = $sth->fetchrow_array() ) {
    foreach (@row) {
        $_ = "NULL" if !defined($_);

# left align if field type is VARCHAR2, else right align
    my $ftyp = $hash1{"$count"};
    my $flen = $hash2{"$count"};

        if ($ftyp eq "VARCHAR2") {
            $cfmt = "%-".$flen."s";
        } else {
            $cfmt = "%".$flen."s";
        }

        printf("$cfmt ", $_);
    $count++;
    }
    print "\n";
    $count=0;
}

$dbh->disconnect if defined($dbh);

$ ./testDBD.pl
EMPNO ENAME      JOB       MGR  HIREDATE   SAL     COMM    DEPTNO 
----- ---------- --------- ---- ---------- ------- ------- ------
 7369 SMITH      CLERK     7902  17-DEC-80     800    NULL     20 
 7499 ALLEN      SALESMAN  7698  20-FEB-81    1600     300     30 
 7521 WARD       SALESMAN  7698  22-FEB-81    1250     500     30 
 7566 JONES      MANAGER   7839  02-APR-81    2975    NULL     20 
 7654 MARTIN     SALESMAN  7698  28-SEP-81    1250    1400     30 
 7698 BLAKE      MANAGER   7839  01-MAY-81    2850    NULL     30 
 7782 CLARK      MANAGER   7839  09-JUN-81    2450    NULL     10 
 7788 SCOTT      ANALYST   7566  19-APR-87    3000    NULL     20 
 7839 KING       PRESIDENT NULL  17-NOV-81    5000    NULL     10 
 7844 TURNER     SALESMAN  7698  08-SEP-81    1500       0     30 
 7876 ADAMS      CLERK     7788  23-MAY-87    1100    NULL     20 
 7900 JAMES      CLERK     7698  03-DEC-81     950    NULL     30 
 7902 FORD       ANALYST   7566  03-DEC-81    3000    NULL     20 
 7934 MILLER     CLERK     7782  23-JAN-82    1300    NULL     10 
$

SQL> select * from emp;

     EMPNO ENAME      JOB           MGR HIREDATE        SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK          7902 17-DEC-80        800            20
      7499 ALLEN      SALESMAN          7698 20-FEB-81       1600        300       30
      7521 WARD       SALESMAN          7698 22-FEB-81       1250        500       30
      7566 JONES      MANAGER          7839 02-APR-81       2975            20
      7654 MARTIN     SALESMAN          7698 28-SEP-81       1250       1400       30
      7698 BLAKE      MANAGER          7839 01-MAY-81       2850            30
      7782 CLARK      MANAGER          7839 09-JUN-81       2450            10
      7788 SCOTT      ANALYST          7566 19-APR-87       3000            20
      7839 KING       PRESIDENT        17-NOV-81       5000            10
      7844 TURNER     SALESMAN          7698 08-SEP-81       1500      0       30
      7876 ADAMS      CLERK          7788 23-MAY-87       1100            20
      7900 JAMES      CLERK          7698 03-DEC-81        950            30
      7902 FORD       ANALYST          7566 03-DEC-81       3000            20
      7934 MILLER     CLERK          7782 23-JAN-82       1300            10

14 rows selected.

SQL>