Okay, what you could do is something like this... Create four hashes, each a relationship of their part number to another hash of "name" => "part_number" relationships. This will make looksups fast, and keep things organized. I've done with a naming scheme / eval strategy in the following code:

use strict;

my $WAI_cat;
my $lester_cat;
my $pic_cat;
my $manu_cat;

my $part_entry = {
  "lester" => "12345",
  "WAI" => "2-2342-01DU",
  "pic" => "340-87",
  "manu" => "72 4223"
};

foreach(keys %$part_entry)
{
 my $str= "\$\$".$_."_cat{'$$part_entry{$_}'} = \$part_entry";  
 #print $str.="\n";
 eval($str);
}

print $$WAI_cat{"2-2342-01DU"}{lester}."\n";     
print $$pic_cat{"340-87"}{manu}."\n";
[download]

You can see that the hashes are named "category type"_cat to save us issues with assigning each by hand (the eval statement takes care of that cleanly). Building this allows you to look parts up by any category, and then you can reference through the hash to the other four parts.

If you don't want to handle four actual hashes, you could probably manage something with a single hash with four named keys to a catalogues of hashes. Note that this solution probably isn't largely optimal on memory, but I don't know how many items in the database you will need to hold. Will this need to go to disk, or just run once? You could use Storable or Data::Dumper to freeze the whole structure to disk if you ever needed to use it again.

    --jb