JPA/休眠-与孩子一起分离实体

问题描述

我正在将JPA 2与Hibernate 3.6.8一起使用.

I'm using JPA 2 with Hibernate 3.6.8 as the implementation.

假设我们有一个实体Foo

@Entity
public class Foo {
    ....
    @OneToOne
    private Bar bar;

    ....
}

我需要从会话中分离整个实体图，并且当我执行entityManager.detach(foo)时，我惊讶地发现bar仍保持连接状态，这与IMO相当不直观.

I need to detach the whole entity graph from the session, and when I do entityManager.detach(foo), I was surprised that bar remained attached, which IMO is quite counter intuitive.

阅读EntityManager上的文档，看来这是预期的情况，因为它没有提及任何与关联/子实体有关的内容:

Reading the documentation on the EntityManager, it appears that this is the expected case since it does not mention anything about associations/child entites:

我也可以简单地调用entityManager.detach(foo.getBar())，但这意味着如果以后添加任何关联，我将必须确保也手动分离了这些关联.

I can simply call entityManager.detach(foo.getBar()) too, but it means that if I add any associations later on, I will have to make sure that those are detached manually too.

是否有任何简便的方法可以实现这一目标而无需依靠反思?

Is there any convenient way to achieve this without resorting to reflection?

推荐答案

添加DETACH类型的级联:

Add a cascade of type DETACH:

@OneToOne(cascade = CascadeType.DETACH)
private Bar bar;

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