Just wanted to report back on my results, which were phenomenal! This script writes the MySQL database to the DBM file:

#!/usr/bin/perl -w

use strict;

use Mojo::DB;
use DBM::Deep;

$| = 1;

my $dbh = get_dbh();
die "No filename argument provided" unless @ARGV;
my $file = shift @ARGV;

unlink $file;

# This is the magic. :-)
my $db = DBM::Deep->new( $file );

tie my %IDS, 'DBM::Deep', $file or die "$!";

my @keys = qw(employee_id firstname lastname title dept salary date_hi
+red);

my $keys = join(', ', @keys);
my $query = "select $keys from employee_data";
my @values = @{$dbh->selectall_arrayref($query)};

for my $v (@values){
    my @vals = @$v; # one ID per array
    for (@vals){
        $_ = '-' unless $_;
    }
    $db->{$vals[0]} = {
        (map {
            $keys[$_] => $vals[$_];
        } 0 .. $#keys)
    };
}
[download]

and this script reads the data back out:

#!/usr/bin/perl -w

use strict;
use DBM::Deep;

$| = 1;

die "No filename argument provided" unless @ARGV;
my $file = shift @ARGV;

tie my %IDS, 'DBM::Deep', $file or die "$!";

while (my($k, $v) = each %IDS){
    print "\n$k :\n";
    while (my ($k, $v) = each %{$v}){
        print "$k => $v\n";
    }
}
[download]

It really works like a dream, thank you so much. The nice thing, too, is that I almost understand how it works! I'm even going to leave your comment about "this is the magic" in there to remind me. : )