如何在drupal 7中提交表单后调用函数

Question

How can we call a function after form submit in drupal 7?

function form_theme_form_submit($form, &$form_state) {
    global $user;

             db_insert('card_detail')
            ->fields(array(
              'card_number' => $_POST['card_number'],
              'card_cvc' => $_POST['card_cvc'],
              'card_expiry_month' => $_POST['card_expiry_month'],
              'card_expiry_year' => $_POST['card_expiry_year'],
              'user_id' => $user->uid,

              ))
            ->execute();
            unset($form); 
            $form_state['rebuild'] = TRUE;

drupal_set_message(t('The form has been submitted.'));
//i want to call function but its not working...
    $card_array = get_card_detail();
  }