print "create hashref\n";
my $closurehash = $sth->fetchall_hashref("name");
foreach $key ( keys(%{$closurehash}) ) { 
    print "$closurehash->{$key}->{'name'}\n";
}
print "add to hashref\n";
$closurehash->{ "test" } = "test";  # hash ref
foreach $key ( keys(%{$closurehash}) ) { 
    print "$closurehash->{$key}->{'name'}\n";
}
print "delete from hashref\n";
delete $closurehash->{"fake35"};  
foreach $key ( keys(%{$closurehash}) ) {
    print "$closurehash->{$key}->{'name'}\n";
}

##</code><code>##

create hashref
fake35
add to hashref

fake35
delete from hashref