That's right, what you have is illegal syntax in either language. You are trying to access a HoH (hash of hashes) instead of what you really have, a LoH (list of hashes). You simply are missing the array index:

genesis['Foxtrot'][0]['instrumental'] = 'excellent'

$gensis->{Foxtrot}[0]{instrumental} = 'excellent';
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Now then, as for populating these datastructures from a database ... well, i can't help you much with Python. You'll have to read the docs, but i can say that Perl's DBI has methods that will form these datastructures for you, methods such as:

• selectall_arrayref
• selectall_hashref
• fetchrow_arrayref
• fetchrow_hashref

and more. I usually only use selectall_arrayref, but sometimes i need the lookup power of hashes. You have to ensure that all of your data has unique id's in order for hashes to work safely (without clobbering existing keys). Recently i decided to roll my own:

# takes prepared statement handle and returns LoH
sub db2tmpl {
    my ($sth) = @_;
    $sth->execute;
    my $fields = $sth->{NAME};
    my $rows   = $sth->fetchall_arrayref;
    my @loh;
    for my $row (@$rows) {
        my %hash;
        @hash{@$fields} = @$row;
        push @loh, {%hash};
    }
    return \@loh;
}
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This is very useful with HTML::Template, though i can't help but feel i am re-inventing a wheel. At any rate, i wish you the best of luck. :)

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)