Here is an example of an oop approach you may find useful.

package component;
my %sc;
sub new { bless { name => "$_[1]" }, 'component'; }
sub name { $_[0]->{name}; }
sub sc  { 
    $sc{$_[0]->name} = [] unless $sc{$_[0]->name};
    push @{$sc{$_[0]->name}}, $_[1]; 
    $_[0]{$_[1]} = new component($_[1]); 
    };
sub label:lvalue { $_[0]->{lbl}; }
sub subs { \@{$sc{$_[0]->name}}; }
1;

package project;
sub new { bless { }, 'project'; }
sub components { my @c; @c = sort keys %{$_[0]}; \@c; }
sub addcomponent {  
    $_[0]->{$_[1]} = new component( $_[1] );  
    $_[0]->{$_[1]};
}
sub show {
  my $proj = shift;
  foreach my $comp ( @{$proj->components} ){
    print "$comp\n";
    next unless $#{$proj->{$comp}->subs} > 0;

    foreach my $sc ( @{$proj->{$comp}->subs} ){
    next unless $proj->{$comp}{$sc};
        print "\t$sc\t" if $sc;
    print $proj->{$comp}{$sc}->label,"\n" 
      if $proj->{$comp}{$sc}->label;
    }
  }
}
1;

use strict;

my $proj = new project();

my $i = 0;
while( <DATA> ){
  $i++; chomp;
  next if $i == 1;
  my ($comp, $subcomp, $label ) = split /\t/, $_;
  my $sw = $proj->{$comp};
  $sw = $proj->addcomponent( $comp ) unless $sw;
  my $sc = $sw->sc($subcomp);
  $sc->label = $label;
}

$proj->show;

my $hw = join ', ', @{$proj->{Hardware}->subs};

print "Hardware subcomponents ( $hw )\n";
my $sw = $proj->{Software};
my $db = $sw->{Database};
my $label = $db->label;

print "$sw->{name} $db->{name} $label\n";


__DATA__
COMPONENT    SUBCOMPONENT    LABEL
Software    Database    Test-1.01
Software    Good Languages    Perl
Software    Sucky Languages    Java
Hardware    Monitor    19" LCD
Hardware    CPU    Pentium 2.4 Ghz
[download]

Cheers,
JamesNC