Or he could do it in a quarter of the time with half the code, without having to download and compile modules or read 1000 lines of documentation and learn SQL.

#! perl -slw
use strict;
use Data::Dumper;


my @fields = split'\|', <DATA>;
chomp $fields[-1];

my %HoH = map{
    chomp;
    my%h;
    @h{ @fields } = split'\|';
    ( $h{ last } . '_' . substr( $h{ first }, 0, 1 ) => \%h )
} <DATA>;

print Dumper \%HoH;

__DATA__
title|first|last|room|phone|email
Mrs|Linda|Caralo|201|148|she@borg.org
Miss|Jean|Androno|317|167|j@alo.com
[download]

prints

P:\test>test2
P:\test>test2
$VAR1 = {
          'Paterman_S' => {
                            'email' => 'steve@net.net',
                            'first' => 'Steve',
                            'last' => 'Paterman',
                            'title' => 'Mr',
                            'phone' => '100',
                            'room' => '101'
                          },
          'Caralo_L' => {
                          'email' => 'she@borg.org',
                          'first' => 'Linda',
                          'last' => 'Caralo',
                          'title' => 'Mrs',
                          'phone' => '148',
                          'room' => '201'
                        },
          'Androno_J' => {
                           'email' => 'j@alo.com',
                           'first' => 'Jean',
                           'last' => 'Androno',
                           'title' => 'Miss',
                           'phone' => '167',
                           'room' => '317'
                         }
        };
[download]