JPA删除所有实体的作品很奇怪 [英] JPA delete all entites works strange

问题描述

我有一个这样的实体关系:

I have an entityrelation like this:

在ParentObj类中:

In the ParentObj class:

@OneToMany(mappedBy = "parentObj", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
private List<ChildObj> list;

在ChildObj类中:

In the ChildObj class:

@JoinColumn(name="PARENT_OBJ")
@ManyToOne
private ParentObj parentObj;

当父对象保留或删除时，子对象也将保留/删除. 但是，当我尝试使用CriteriaDelete删除所有实体时，例如:

When the parent object persisted or removed, the child is persisted/removed as well. BUT when I try to remove all the entities with a CriteriaDelete like:

CriteriaDelete<ParentObj> query = builder.createCriteriaDelete(ParentObj.class);
            query.from(ParentObj.class);
            em.createQuery(query).executeUpdate();

或类似这样的简单查询:

or a simple query like this:

em.createQuery("DELETE FROM ParentObj po").executeUpdate();

我收到了ConstraintViolationException，有人可以解释为什么会这样吗?

我使用的是org.hibernate.ejb. HibernatePersistence 提供程序和 JTA 在 Wildfly 服务器上.

I'm using org.hibernate.ejb.HibernatePersistence provider with JTA on a Wildfly server.

推荐答案

以下

em.createQuery("DELETE FROM ParentObj po").executeUpdate(); 

是JPQL批量更新命令，并且作为JPQL语言参考说明:

is a JPQL bulk update command and as the JPQL language reference notes:

10.2.9. JPQL批量更新和删除

10.2.9. JPQL Bulk Update and Delete

操作批量更新和删除操作适用于的实体 单一实体类(及其子类，如果有的话).

Operations Bulk update and delete operations apply to entities of a single entity class (together with its subclasses, if any).

删除操作仅适用于指定类的实体，并且 它的子类. 它不会级联到相关实体. ....

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

https://docs.oracle.com/html/E24396_01/ejb3_langref. html#ejb3_langref_bulk_ops

因此，实质上，您正在尝试删除一个实体，由于缺少级联，该实体在数据库中仍将具有FK引用.因此，例外.

So essentially you are attempting to remove an entity which, due to lack of cascading, will still have FK references in the database. Hence the exception.

CriteriaDelete具有类似的限制:

CriteriaDelete has similar limitations:

https://docs.oracle.com/javaee/7/api/javax/persistence/criteria/CriteriaDelete.html

标准API批量删除操作直接映射到数据库删除操作.持久性上下文与 批量删除的结果.

Criteria API bulk delete operations map directly to database delete operations. The persistence context is not synchronized with the result of the bulk delete.

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