JPA @Version行为

Question

即时通讯使用JPA2和Hibernate 3.6.x.

我在@Version上做了一个简单的测试.

假设我们有2个实体,

1. 实体团队有一个玩家实体列表,双向关系,懒惰fetchtype,级联类型全部
2. 两个实体都有@Version

以下是场景:

1. 每当对团队/玩家实体之一进行修改时,团队/玩家的版本将在刷新/提交时增加(修改后的记录上的版本增加).

2. 使用持久性将新的玩家实体添加到团队的集合中,在持久化之后将为团队的版本分配实体(添加新实体,新实体将获得它的版本).

3. 每当对其中一个玩家实体进行添加/修改/删除时,团队的版本将在刷新/提交时增加.(添加/修改/删除子记录,父版本也增加了)

我能理解数字1和2,但数字3,我不明白,为什么团队的版本增加了？

这让我想到了其他问题:

1. 如果我有父< - >孩子< - > granchildren关系船怎么办？孙子孙女的加法或修改会增加孩子和父母的版本吗？
2. 在方案2中,如何在提交之前获得团队版本,例如使用flush？在我们对孩子做某事之后,这是一种推荐的获得父母版本的方法吗？

---

这是我的实验中的代码示例,证明当ReceivingGoodDetail是拥有方时,并且在刷新后版本在ReceivingGood中增加了.很抱歉,这使用其他实体,但ReceivingGood就像团队一样,ReceivingGoodDetail就像玩家一样.1 ReceivingGood/Team,很多ReceivingGoodDetail/Player.

/*
Hibernate: select receivingg0_.id as id9_14_, receivingg0_.creationDate as creation2_9_14_, .. too long
Hibernate: select product0_.id as id0_4_, product0_.creationDate as creation2_0_4_, .. too long
before persisting the new detail, version of header is : 14
persisting the detail 1c9f81e1-8a49-4189-83f5-4484508e71a7
printing the size of the header : 
Hibernate: select details0_.receivinggood_id as receivi13_9_8_, details0_.id as id8_, details0_.id as id10_7_, .. too long
7
after persisting the new detail, version of header is : 14
Hibernate: insert into ReceivingGoodDetail (creationDate, modificationDate, usercreate_id, usermodify_id, version, buyQuantity, buyUnit, internalQuantity, internalUnit, product_id, receivinggood_id, supplierLotNumber, id) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: update ReceivingGood set creationDate=?, modificationDate=?, usercreate_id=?, usermodify_id=?, version=?, purchaseorder_id=?, supplier_id=?, transactionDate=?, transactionNumber=?, transactionType=?, transactionYearMonth=?, warehouse_id=? where id=? and version=?
after flushing, version of header is now : 15
    */
public void addDetailWithoutTouchingCollection() {
    String headerId = "3b373f6a-9cd1-4c9c-9d46-240de37f6b0f";
    ReceivingGood receivingGood = em.find(ReceivingGood.class, headerId);

    // create a new detail
    ReceivingGoodDetail receivingGoodDetailCumi = new ReceivingGoodDetail();
    receivingGoodDetailCumi.setBuyUnit("Drum");
    receivingGoodDetailCumi.setBuyQuantity(1L);
    receivingGoodDetailCumi.setInternalUnit("Liter");
    receivingGoodDetailCumi.setInternalQuantity(10L);
    receivingGoodDetailCumi.setProduct(getProduct("b3e83b2c-d27b-4572-bf8d-ac32f6de5eaa"));
    receivingGoodDetailCumi.setSupplierLotNumber("Supplier Lot 1");
    decorateEntity(receivingGoodDetailCumi, getUser("3978fee3-9690-4377-84bd-9fb05928a6fc"));
    receivingGoodDetailCumi.setReceivingGood(receivingGood);

    System.out.println("before persisting the new detail, version of header is : " + receivingGood.getVersion());

    // persist it
    System.out.println("persisting the detail " + receivingGoodDetailCumi.getId());
    em.persist(receivingGoodDetailCumi);

    System.out.println("printing the size of the header : ");
    System.out.println(receivingGood.getDetails().size());

    System.out.println("after persisting the new detail, version of header is : " + receivingGood.getVersion());

    em.flush();

    System.out.println("after flushing, version of header is now : " + receivingGood.getVersion());
}

Answer 1

它看起来像是Hibernate中的一个bug.

JPA规范说:

所有非关系字段和属性以及实体拥有的所有关系都包含在版本检查中

但是,Hibernate也会在更改非拥有关系属性后增加版本(例如,EclipseLink不会这样做).可以通过@OptimisticLock(exclude = true)在属性上设置来禁用此行为.

请注意,它仅适用于关系属性本身的更改,而不适用于引用对象状态的更改,因此父级版本不会因孙子集合的更改而发生更改.