I have recently discovered a fairly new project, Dancer and a fairly old one, SQL::Translator. The following code details a Dancer handler which, with the proper credentials supplied will translate the given database into either a text file which contains the create definitions to create a schema or a PNG file that contains an ER diagram of the schema. MySQL is the target database, but others should work as well.

use Dancer ':syntax';
use SQL::Translator;

get '/render' => sub {
    my $db = params->{db};
    my $format = params->{format} || 'text';

    my $translator = SQL::Translator->new(
        from        => 'DBI',
        to          => 'MySQL',
        parser_args => {
            dsn         => "dbi:mysql:$db",
            db_user     => '',
            db_password => '',
        },
    );
    my $sql = $translator->translate( data => '' );

    if ($format eq 'text') {
        content_type 'text';
        return $sql;
    }
    elsif ($format eq 'png') {
        content_type 'png';
        my $translator = SQL::Translator->new(
            from          => 'MySQL',
            to            => 'GraphViz',
            producer_args => {
                output_type   => 'png',
                natural_join  => 1,
            },
        );
        return $translator->translate( data => $sql );
    }
};
[download]

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)