休眠：@ManyToOne（fetch = FetchType.LAZY）不适用于非主键引用列 [英] Hibernate: @ManyToOne(fetch = FetchType.LAZY) does not work on non-primary key referenced column

问题描述

我有两个表格： Order [OrderId（PK），OrderShipmentCode，...] 和 Shipment [ShipmentId（PK），ShipmentCode， ... 。

在 Order 类中，声明了
$ b

  @ManyToOne（fetch = FetchType.LAZY）
 @JoinColumn（name =OrderShipmentCode，referencedColumnName =ShipmentCode，insertable = false，updatable = false，nullable = false）
 private装运货物; 
  

当我得到 Order 的列表时， Shipment 也被加载（我看到很多单独的SELECT查询）。但是我希望 Shipment 被延迟加载，而不是与 Order一起被提取。

对于其他表，如果被引用的列是主键，那么结果如预期（使用延迟加载）。在我的情况下， ShipmentCode 不是 Shipment 表的主键，Hibernate不使用延迟加载。 / p>

你能告诉我如何实现这个目标吗？

编辑：
查询代码如下：

  Criteria criteria = HibernateUtil.getSessionFactory（）。getCurrentSession（）。createCriteria（Order。类）; 
列表结果= criteria.list（）; 
  

SQL查询有：1个用于 Order table和一堆SELECT语句用于 Shipment

解决方案

试试这个：



  Criteria criteria = HibernateUtil.getSessionFactory（）
 .getCurrentSession（）
 .createCriteria（Order。 class）
 .setFetchMode（shipment，FetchMode.LAZY）; 
  




I have 2 tables: Order [OrderId(PK), OrderShipmentCode, ...] and Shipment[ShipmentId(PK), ShipmentCode, ...].

In Order class, I declared shipment field as follows:

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "OrderShipmentCode", referencedColumnName = "ShipmentCode", insertable = false, updatable = false, nullable = false)
private Shipment shipment;

When I get the list of Order, the Shipment is also loaded (I saw many separate SELECT queries). But I want the Shipment to be lazy loaded, not to be fetched together with Order.

For other tables, if the referenced column is primary key then the results are as expected (Lazy-loading is used). In my case, ShipmentCode is not Primary Key of Shipment table, and lazy-loading is not used by Hibernate.

Could you show me how to accomplish that goal?

EDIT: The Query code is as bellow:

Criteria criteria = HibernateUtil.getSessionFactory().getCurrentSession().createCriteria(Order.class);
List result = criteria.list();

SQL queries are: 1 SELECT statement for Order table and a bunch of SELECT statement for Shipment

解决方案

Try this:

Criteria criteria = HibernateUtil.getSessionFactory()
                                 .getCurrentSession()
                                 .createCriteria(Order.class)
                                 .setFetchMode("shipment", FetchMode.LAZY);

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