config.yml

port: 4002
dsn: "dbi:SQLite:dbname=test.db"

dancerdbtest.pl

#!/usr/bin/perl

use Dancer;
use DBI;

{
    my $database;
    sub database { return $database ||= DBI::connect(setting('dsn')); }
}

get '/' => sub {
    my $sth = database()-prepare('select * from mytable');
    $sth->execute;
    while (my $row = $sth->fetchrow_hashref) {
        print "<p>$row->{foo}</p>";
    }
};