Полезные решения для Codeigniter

$this->form_validation->set_rules('email', 'Email', 'required|valid_email|unique[user.email]');

class MY_Form_validation extends CI_Form_validation {  
 
    function unique($value, $params) {  
 
        $CI =& get_instance();
        $CI->load->database();  
 
        $CI->form_validation->set_message('unique',
            'The %s is already being used.');  
 
        list($table, $field) = explode(".", $params, 2);  
 
        $query = $CI->db->select($field)->from($table)
            ->where($field, $value)->limit(1)->get();  
 
        if ($query->row()) {
            return false;
        } else {
            return true;
        }  
 
    }
}