#!/usr/bin/perl -w
use strict;
use DBI;
use DBD::Oracle;

my $db1 = DBI->connect("dbi:Oracle:server=XXXX;database=XXXX", "USER","PASSWD")
        or die "Failed to connect to the database!";

my $db2 = DBI->connect("dbi:Oracle:server=XXXX;database=XXXX", "USER","PASSWD")
        or die "Failed to connect to the database!";
        
my $table = "DUMMY";        # name of the table
my $unique_id = "ID";       # unique id to identify the row

my $sth1 = $db1->prepare( "select * from $table" );
my $sth2 = $db2->prepare( "select * from $table where $unique_id=?" );

$sth1->execute();
while (my $row = $sth1->fetchrow_hashref())
{
    my $found = 0;

    $sth2->execute( $row->{$unique_id} );
    while (my $row2 = $sth2->fetchrow_hashref()) {
        # compare the row
        foreach (keys %$row) {
            if ($row{$_} ne $row2{$_}) {
               print "DIFF: (ID) $_\n";
               break;
            }
        }
    }
}

$sth->finish;
$dbh->disconnect;