what is the best practice Business validation in transaction scope or out of tx scope  for EJB ?

-------------------------------------------------Validation in Not Tx scope ------------------------------------------------------------------

@Stateless

public class CustomerBean implements CustomerBeanLocal {

    private EntityManager em;

    @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)

    public void isValidCustomer(Customer customer) {

       // perform some validation for customer related db query

        if (customer != null) {

            isCustomerActive(customer);

        }

        createOrder(customer);

    }

    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)

    private void createOrder(Customer customer) {

        em.persist(customer);

   }

}

===========================Validation in Tx scope =============================================

@Stateless

public class CustomerBean implements CustomerBeanLocal {

    private EntityManager em;

    @TransactionAttribute(TransactionAttributeType.REQUIRED)

    private void createOrder(Customer customer) {

       // perform some validation for customer related

        if (customer != null) {

            isCustomerActive(customer);

        }

        em.persist(customer);

   }

}

===========================================

Which one is best and why best ?????????