无法级联删除@OneToOne成员

@Entity public class Organization {

    @OneToOne(fetch = FetchType.EAGER)
    @OnDelete(action = OnDeleteAction.CASCADE)
    @Cascade(value = DELETE_ORPHAN)
    private Days days;

}

I have the following entity definition and it generates a SQL to do a cascade delete on the @OneToOne entry when the parent object gets deleted. But it's not removing the "days" entry while deleting an Organization.

我有以下实体定义，它会生成一个SQL，以便在删除父对象时对@OneToOne条目执行级联删除。但是在删除组织时不会删除“days”条目。

This happens with h2, mysql databases, what could be the problem here.

这发生在h2，mysql数据库中，这可能是什么问题。

2 个解决方案

#1

My query looks like this "delete from Organization where some_key_id = ?" (am not deleting this based on primary key id)

我的查询看起来像这样“从组织中删除some_key_id =？” （我不是根据主键ID删除它）

A bulk delete (you should mention that in your question) doesn't cascade to anything. Quoting the JPA 1.0 specification:

批量删除（你应该在你的问题中提到）不会级联到任何东西。引用JPA 1.0规范：

4.10 Bulk Update and Delete Operations

...

...

A delete operation only applies to entities of the specified class and its subclasses. It does not cascade to related entities.

删除操作仅适用于指定类及其子类的实体。它不会级联到相关实体。

This is a very annoying limitation and there are many RFEs to improve things (HHH-695, HHH-1917, HHH-3337, HHH-5529, etc).

这是一个非常烦人的限制，有很多RFE可以改善（HHH-695，HHH-1917，HHH-3337，HHH-5529等）。

For now, possible solutions include:

目前，可能的解决方案包括：

clean up the child table yourself
自己清理孩子桌子
use cascading foreign keys in the schema.
在架构中使用级联外键。

Now the weird part... My understanding of @OnDelete(action = OnDeleteAction.CASCADE) is that this annotation is supposed to be used to ensure that the foreign key is created with the appropriate ON DELETE CASCADE clause (solution #2). In other words, I'd expect things to work.

现在奇怪的部分......我对@OnDelete（action = OnDeleteAction.CASCADE）的理解是，这个注释应该用于确保使用适当的ON DELETE CASCADE子句创建外键（解决方案＃2）。换句话说，我希望事情能发挥作用。

Did Hibernate generate the Organization table? Can you check the DDL? Do you see the expected ON DELETE CASCADE? If not, add it.

Hibernate是否生成了Organization表？你能看看DDL吗？你看到了预期的ON DELETE CASCADE吗？如果没有，请添加它。

#2

Well, I guess you should add a

好吧，我想你应该添加一个

@Cascade(value = {DELETE, DELETE_ORPHAN})

Note that in JPA 2.0 you don't have to use the hibernate-sepcific @Cascade annotation - @*ToMany has an option to delete orphans.

请注意，在JPA 2.0中，您不必使用hibernate-sepcific @Cascade注释 - @ * ToMany可以选择删除孤儿。

Update: when using queries cascades are not handled. You have to handle them manually. This is expected and documented behaviour.

更新：使用查询时，不会处理级联。你必须手动处理它们。这是预期和记录的行为。

#1