use DBI;
my $dbh = 0;

sub connect_db {
   if (defined $dbh) {
        eval {
            $dbh->ping;
        };
        if (!$@) {
            #success return preserver database handle
            return $dbh;
        }
    }
      #ok, create a new database handle
        my $retry_count = 5;
        while ((!$dbh) && ($retry_count > 0)) {
                $dbh = DBI->connect('dbi:Oracle:linuxdb3','scott', 'tiger');
                $retry_count -= 1;
                sleep(1);
        }

        if (!$dbh) {
            # Database connection failed
            return 0;
        }
         # Database connection OK
        return $dbh;
}

sub disconnect_db {
    if (defined $dbh) {
        eval {
            $dbh->ping;
        };
        if ($@) {
            # Database handle invalid as ping failed
            return 0;
        }
    }
            # Disconnect Database connection
        $dbh->disconnect;
        return 1;
}