java - Hibernate saveOrUpdate 方法会删除 child 吗？

Question

我有一个应用程序通过 hibernate 加载对象，然后将这些对象作为分离对象传递到另一层。对这些对象所做的任何更改都会向下发送回 hibernate 层，在 hibernate 层中我会在这些对象上调用 saveOrUpdate()。

如果我在调用 之前简单地从集合中删除子对象，hibernate 是否会删除传递给 saveOrUpdate() 的对象中包含在集合中的一对多关系子对象保存或更新()？

如果不是，那么这通常如何在使用分离对象的 hibernate 应用程序中完成？

Answer 1

Will hibernate delete one-to-many relationship child objects contained in a collection in the objects that are passed into saveOrUpdate() if I simply remove the child object from the collection before calling saveOrUpdate()?

不，不是默认情况。在这种情况下，此类子对象被称为“孤儿”，假设其他实体也没有对它们的引用。

这在文档中进行了讨论，11.11. Transitive persistence :

A special cascade style, delete-orphan, applies only to one-to-many associations, and indicates that the delete() operation should be applied to any child object that is removed from the association. Using annotations there is no CascadeType.DELETE-ORPHAN equivalent. Instead you can use the attribute orphanRemoval as seen in Example 11.4, “@OneToMany with orphanRemoval”. If an entity is removed from a @OneToMany collection or an associated entity is dereferenced from a @OneToOne association, this associated entity can be marked for deletion if orphanRemoval is set to true.