By Role Name

role.php

<?php defined('SYSPATH') or die('No direct script access.');

class Model_Role extends Model_AutoModeler_ORM_Role{
	public static function get_role_by_name($name)
	{
		$role = new self();
		$role->load(DB::select()->where('name', '=', $name));
		return $role;
	}
}