jpa hibernate @OneToOne @JoinColumn referencedColumnName被忽略 [英] jpa hibernate @OneToOne @JoinColumn referencedColumnName ignored

问题描述

在对与另一个实体具有一对一关系的实体执行jpql查询时，遇到意外行为。关键是，关系是从根实体的主键到目标实体的非ID的字段。

以下是示例：

  //根实体
 @实体
 @Table（name =PERSON）
 
 public class Person {
 
 @Id 
 @Column（name =PERSON_ID）
私人长ID; 
 
私人字符串名称; 
 
 @OneToOne（可选= false）
 @JoinColumn（name =PERSON_ID，referencedColumnName =PERSON_ID，insertable = false，updatable = false，unique = true）
私人地址mainAddress; 
 ... 
 
 //引用实体
实体
表（名称=ADDRESS）
公共类地址{
 
 @Id 
 @Column（name =ADDRESS_ID）
私人长ID; 
 
 @Column（name =PERSON_ID）
 private long personId; 
 ... 
} 
  

以下jpql查询：

 从Person p中选择p left join fetch p.mainAddress 
  

生成以下ORACLE SQL查询：

  SELECT ... FROM PERSON p LEFT OUTER加入地址a p.PERSON_ID = a.ADDRESS_ID 
  

虽然我期望：

  SELECT ... FROM PERSON p LEFT OUTER JOIN ADDRESS a ON p.PERSON_ID = a.PERSON_ID 
  

基本上， referencedColumnName =PERSON_ID属性的属性将被忽略，并且会在主键上执行连接。

有人可以请我解释一下为什么？

解决方案

c> @OneToOne 按原样映射，外键将出现在Person表中，即。 Person表（如果你没有在@JoinColumn注解中指定person_id）应该有一个FK列'address_id'。

形成你期望生成的SQL的外观像，它会出现你想FK在地址表中，即地址有一个FK列person_id。你可以这样做：

  @Entity 
 @Table（name =PERSON）
 
 public class Person {
 
 @Id 
 @Column（name =PERSON_ID）
私人长ID; 
 
私人字符串名称; 
 
 @OneToOne（mappedBy =person）
 private地址mainAddress; 
 
 
 
 $ b @Entity 
 @Table（name =ADDRESS）
公共类地址{
 
 @Id 
 @Column（name =ADDRESS_ID）
私人长ID; 
 
 @OneToOne（可选= false）
 @JoinColumn（name =PERSON_ID，可插入= false，可更新= false，唯一= true）
私人person person; 
 
} 
  

I am experiencing an unexpected behavior while performing a jpql query on an entity having a one-to-one relationship with another. The key point is that the relationship is from the primary key of the root entity to a field of the destination entity which is not the ID.

Here is the example:

// root entity
@Entity
@Table(name = "PERSON")

public class Person {

    @Id
    @Column(name = "PERSON_ID")
    private long id;

    private String name;

    @OneToOne(optional = false)
    @JoinColumn(name = "PERSON_ID", referencedColumnName = "PERSON_ID", insertable = false, updatable = false, unique = true)
    private Address mainAddress;
    ...
}
// referenced entity
@Entity
@Table(name = "ADDRESS")
public class Address {

    @Id
    @Column(name = "ADDRESS_ID")
    private long id;

    @Column(name = "PERSON_ID")
    private long personId;
    ...
}

The following jpql query:

select p from Person p left join fetch p.mainAddress

Produces the following ORACLE SQL query:

SELECT ... FROM PERSON p LEFT OUTER JOIN ADDRESS a ON p.PERSON_ID = a.ADDRESS_ID

While I expected :

SELECT ... FROM PERSON p LEFT OUTER JOIN ADDRESS a ON p.PERSON_ID = a.PERSON_ID

Basically the attribute of the referencedColumnName = "PERSON_ID" attribute is ignored and the join is performed on the primary key.

Somebody can please explain me why?

解决方案

With the @OneToOne mapped as it is, the foreign key is going to be in the Person table, viz. the Person table (if you hadn't specified person_id in the @JoinColumn annotation) should have a FK column 'address_id'.

Form what you expect the generated SQL to look like, it would appear that you want the FK to be in the address table i.e. address has a FK column person_id. You can do this by as follows:

@Entity
@Table(name = "PERSON")

public class Person {

    @Id
    @Column(name = "PERSON_ID")
    private long id;

    private String name;

    @OneToOne(mappedBy = "person")
    private Address mainAddress;

}


@Entity
@Table(name = "ADDRESS")
public class Address {

    @Id
    @Column(name = "ADDRESS_ID")
    private long id;

    @OneToOne(optional = false)
    @JoinColumn(name = "PERSON_ID", insertable = false, updatable = false, unique = true)
    private Person person;

}

这篇关于jpa hibernate @OneToOne @JoinColumn referencedColumnName被忽略的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！