check-field-exist

<!------begin   controller--->

$this->form_validation->set_rules('sli_status', 'Status', 'trim|required|callback_isExist');
$this->form_validation->set_error_delimiters('<font color="red">', '</font>');

if ($this->form_validation->run() == FALSE)
		{

		}
else {
	//do insert database
}

public function isExist() {
    $is_exist = $this->model_slide->isExist();
	if ($is_exist) {
        $this->form_validation->set_message(
            'isEmailExist', 'Status dengan classa ctive sudah ada'
        );
        return false;
    } else {
        return true;
    }
}




<!----------------------model ------------------------->
function isExist() {
$this->db->where('sli_status','active');
$this->db->select("*");
$this->db->from("slide");
$query=$this->db->get();
 if ($query->num_rows() > 0) {
        return true;
    } else {
        return false;
    }
}