use overload
	'""'     => sub { shift->{'name_lc'} },
	fallback => 1;
[...]
sub new {
	my ($class, $name) = @_;
	return $class->SUPER::new(
		{
			name        => $name,
			name_lc     => lc($name),
			_groups     => {},
			placeholder => '?'
		}
	);
}

sub name_lc { shift->{'name_lc'} }

##</code><code>##

%Time    Sec.     #calls   sec/call  F  name
14.67   55.4872  2174052   0.000026     <anon>:...5.8.2/Class/DBI/Column.pm:37
 9.55   36.1474  2178574   0.000017     Class::DBI::Column::name_lc