插入时发生Hibernate异常

Question

我有两个表的应用程序，先生我正在使用JPA，Hibernate的ORM映射。插入记录时出现问题。请帮帮我。

* Mr_id in application table is a foreign key

* code in mr table is unique key

* mr_id in MR table is primary key

应用程序表：

(id，mr_id)

(1，空)

(2，空)

MR表：

(mr_id，代码，名称)

(1，code1，mr1)

(2，code2，mr2)

I have a jpa repository :   ApplicationRepository

application = Application(1)

application.mr = MR(1,code1,mr1)

when I run  : applicationRepository.save(applications[0])
it causes a problem

Reason: Mr record with (1,code1,mr1) alredy present in mr table. 

How to solve this problem with JPA, Hibernate annotation

---------------------------------
    Application {
       @Id
       var id: Int;

       @ManyToOne(cascade = [(CascadeType.PERSIST)])
       @JoinColumn(name = "mr_id")
       var mr: MR? = null
    }

Answer 1

我认为发生这种情况是因为JPA试图在persist之后持久化MR (因为它们是分离的)，但是mr_id =1的MR已经存在。尝试查找mr_id =1(不是create)的mr，并将此mr设置为application.mr