使用元素集合时如何在JPA中执行批量删除？ [英] How to do bulk delete in JPA when using Element Collections?

问题描述

当 Person 对象包含使用 @ElementCollection存储的数据时，我无法解决如何使用JPA批量删除 Person 对象。

  @Entity 
 @Table（name =at_person ）
 public class Person implements Comparable< Person> {
 
 @Id 
 @GeneratedValue（strategy = GenerationType.AUTO）
 @Column（name =id）
 private long id = 0; 
 
 @Column（name =name，nullable = true，length = 128）
 private String name =; 
 
 @ElementCollection 
 @Column（name =email）
 @CollectionTable（name =person_email，joinColumns = @JoinColumn（name =person_id））
私人设置< String> email = new HashSet< String>（）; 
} 
  

目前我正在做的是这样的，键约束错误：

 查询查询= em.createQuery（DELETE FROM Person）; 
  

导致：java.sql.SQLException：完整性约束冲突：
外键不行动; FKCEC6E942485388AB表：PERSON_EMAIL

如果它可以是纯粹的JPA注释而不是Hibernate注释，那将是一种奖励！

解决方案

我会让你解释JPA 2.0规范的一部分，它提到批量删除操作没有级联：

4.10批量更新和删除操作

... ...

...

删除操作仅适用于指定类的
实体和
其子类。 它不会级联到
相关实体。

事实是，Hibernate赢得了'将级联删除到集合表中。这已在 HHH-5529 中报告，建议的方法是：

您也可以（a）自己清理集合表或（b）在模式中使用级联外键。换句话说，（a）使用本机SQL或（b）在数据库级别使用级联删除约束 - 并且您必须添加它（b

手动，我不认为你可以使用 @ElementCollection 注释（与 @OnDelete href =http://opensource.atlassian.com/projects/hibernate/browse/HHH-4301 =noreferrer> HHH-4301 IMO）。

I am having trouble working out how to do a bulk delete of a Person object using JPA, when the Person objects contain data stored using an @ElementCollection. Any ideas on how to do this would be much appreciated.

@Entity
@Table(name="at_person")
public class Person implements Comparable<Person> {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="id")
    private long id = 0;

    @Column(name="name", nullable = true, length = 128)
    private String name = "";

    @ElementCollection
    @Column(name = "email")
    @CollectionTable(name = "person_email", joinColumns = @JoinColumn(name = "person_id"))
    private Set<String> email = new HashSet<String>();
}

What I am doing at the moment is this, and it fails with a foreign key constraint error:

Query query=em.createQuery("DELETE FROM Person");

Caused by: java.sql.SQLException: integrity constraint violation: foreign key no action; FKCEC6E942485388AB table: PERSON_EMAIL

If it can be a pure JPA annotation rather than a Hibernate annotation that would be a bonus!

解决方案

I'll let you interpret the part of the JPA 2.0 specification that mentions that a bulk delete operation is not cascaded:

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.

And the fact is that Hibernate won't cascade a delete to a collection table either. This has been reported in HHH-5529 and the suggested approaches are:

You could also (a) clean up the collection table yourself or (b) use cascading foreign keys in the schema.

In other words, (a) use native SQL or (b) use a cascade delete constraint at the database level - and you'll have to add it manually, I don't think you can use @OnDelete with the @ElementCollection annotation (same story as HHH-4301 IMO).

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