我有两个实体Product和Order，每当创建订单时，我都会更新产品的order_id我尝试应用乐观锁，以便在获取产品以检查其orderId是否为空，然后用新的orderId更新orderId的过程中，没有其他线程通过。2我如何通过@Transaction和@Version来确保这一点呢？3甚至更新查询也没有改变版本。4我是否应该为版本控制做一些模式上的改变呢？
订单存储库

@Modifying
    @Transactional
    @Query("Update ProductEntity p set p.orderId = :orderId " +
            "where p.productId = :productId")
    void updateProductByOrderId(Long orderId, Long productId);

@Data
@Builder
@Entity
@NoArgsConstructor
@AllArgsConstructor
@DynamicUpdate
// @Table
public class ProductEntity {

    public ProductEntity(String brandName, double price) {
        this.brandName = brandName;
        this.price = price;
    }

    @GeneratedValue(strategy = GenerationType.AUTO)
    @Id
    private Long productId;

    @Column
    private String brandName;

    @Column
    private Double price;

    @Nullable
    @Column(name = "fk_order_id")
    private Long orderId;

    @Version
    @Column(name = "version")
    private Long version;

@Transactional
    public OrderEntity createOrder(OrderReq orderReqBody) throws Exception {
        List<ProductEntity> productList = new ArrayList<>();
        for (long id : orderReqBody.getProductIdList()) {
            ProductEntity productEntity = this.productRepository.findById(id).get();
            if (productEntity.getOrderId() != null) {
                throw new Exception("one or more product(s) are unavailable");
            }
            productList.add(productEntity);
        }
        
        OrderEntity toSave = OrderEntity.builder()
                .amount(orderReqBody.getAmount())
                .createdAt(LocalDateTime.now())
                .build();
        OrderEntity orderEntityDB = this.orderRepository.saveAndFlush(toSave);
        for (ProductEntity p : productList) {
            this.productRepository.updateProductByOrderId(orderEntityDB.getOrderId(), p.getProductId());
        // i am attaching a debuggger at this line and 
running an update query via workbench, 
still the version remains the same and both are able to update.

        return orderEntityDB;
    }