__PACKAGE__->load_components("InflateColumn::DateTime");
...
__PACKAGE__->add_columns(
  "start_time",
  {
    data_type   => "datetime",
    is_nullable => 1,
    original    => { data_type => "date" },
  },
);

##</code><code>##

$resultset = $schema->resultset('Ical')
                    ->search({ uid => $id });

##</code><code>##

my $schema = Timetable::Schema->connect("dbi:Oracle:$schema_name",
                        $db_username, $db_password,
                        {on_connect_call => 'datetime_setup'}
                );