use strict;
use warnings;

use Data::Dumper;
use Tie::RefHash;

tie my %h, "Tie::RefHash";

my $key_hash_1 =
  { 'day' => 1, 'month' => 1, 'year' => 2000, 'hour' => 4, 'minute' => 44 };
my $key_hash_2 =
  { 'day' => 1, 'month' => 1, 'year' => 2000, 'hour' => 4, 'minute' => 45 };

%h = (
    $key_hash_1 =>
      { 'burgers_sold' => 5, 'fries_sold' => 3, 'sodas_sold' => 11 },
    $key_hash_2 => { 'burgers_sold' => 2, 'fries_sold' => 4, 'sodas_sold' => 7 }
);

print Dumper( $key_hash_1, $key_hash_2 );
print Dumper( \%h );

for ( keys %h ) {
    print join ' ' => %{$_}, ' => ', %{ $h{$_} }, $/;
}