#!/usr/bin/perl

use strict;
use Data::Dumper;
my $form = "%30s  %s\n";

my %upgrades;
my %lvl;
my %PofC = (
    1   => 2
,   3   => 2
,   4   => 2
,   2   => 5
,   6   => 5
,   7   => 4
,   5   => undef
,   8   => 4
);
print Dumper \%PofC;

foreach my $child (keys %PofC) {
    $lvl{$child} = 0;
}

my $leftovers = 1;
my $level = 0;
while ($leftovers > 0) {
    %upgrades = ();
    $leftovers = 0;
    foreach my $child (keys %PofC) {
        if (exists $lvl{$PofC{$child}}
        &&  $lvl{$PofC{$child}} == $level)
        {
            $upgrades{$child} = 1;
            ++$leftovers;
        }
    }
    foreach (keys %upgrades) {
        ++$lvl{$_};
    }
    ++$level;
}

print Dumper \%lvl;

printf $form, 'child', 'parent';
foreach my $c ( sort { $lvl{$a} <=> $lvl{$b} } keys %lvl ) {
    printf $form, $c, $PofC{$c};
}


exit;

__OUTPUT__
# %PofC
$VAR1 = {
          1 => 2,
          2 => 5,
          3 => 2,
          4 => 2,
          5 => undef,
          6 => 5,
          7 => 4,
          8 => 4
        };
# %lvl
$VAR1 = {
          1 => 2,
          2 => 1,
          3 => 2,
          4 => 2,
          5 => '0',
          6 => 1,
          7 => 3,
          8 => 3
        };
                         child  parent
                             5  
                             2  5
                             6  5
                             4  2
                             3  2
                             1  2
                             7  4
                             8  4
[download]

Thanks a lot for your solution!!!

one way is to use a recursive sub, that 'walks' up the userid tree until it reaches a node without a manager (or a special id (like 0 or undef)

the other way is do the same as above, but use a stack and a loop

some pseudo code

# simple recursive sub
sub create_users {
my $user_href = shift;
my $userId = shift;

if(defined $user_href->{$userId} and $user_href->{$userId} != 0) {
create_users($user_href, $userId);
} else {
return;
}

# now write the user to the db
write_user_to_db($user_href, $userId

}
[download]

I think the above should work :-)

Highly data dependent, but it looks like reverse sorting the keys you want will get the managers in first.

On the other hand, I don't see why you need to have a key in place before you duplicate it as a value. Writing,

my %organization = (
    1234 => '6789',
    1235 => "6790',
    6789 => '6791',
    1236 => '6789',
);
[download]

foreach my $emp (values %hash) {
   print "ERROR: $emp not defined\n" unless exists($hash{$emp});
}
[download]