sub _mk_column_accessors {
    my $class = shift;
    my @new = grep {!exists &{$class."::$_"}} @_; # remember new ones
    $class->SUPER::_mk_column_accessors( @_ ); # accessors + mutators

# Redefine accessors to be very lean

    no warnings 'redefine';
    no strict 'refs';
    foreach (@new) {
        my $method = $class."::$_";
        my $old = \&$method;
        *$method = sub {
# if not available yet, got fetch with normal accessor
            return $old->( @_ ) unless exists $_[0]->{$_};
            $_[0]->{$_};
        };
    }
} #_mk_column_accessors