开发者

Mock JOINED inheritance strategy without actual inheritance

I want to use mixed @Inheritance strategy, but Hibernate doesn't support it.

Is there any way to implement JOINED inheritance without actual class inheritance. For example:

@Entity
@Table(name="A")
@Inheritance(strategy=InheritanceType.JOINED)
public class A { 
  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ID_SEQ")
  private Long id;

  //getters
  //setters
}

@Entity
@Table(name="B")
@Inheri开发者_Go百科tance(strategy=InheritanceType.SINGLE_TABLE)
public class B {
  @Id
  private Long id;

  //getters
  //setters
}

So, basically in B I just want to refer to @Id generated in A without extending from A.


I found the solution. JPA doesn't allow you to combine @Id and @OneToOne. However, @MapsId annotation does the trick:

@Entity
public class A { 
  @Id
  private Long id;

  //getters
  //setters
}

@Entity
public class B {
  @Id
  private Long id;

  @MapsId
  @OneToOne(optional=false, fetch=FetchType.EAGER)
  @JoinColumn(nullable=false, name="id")
  private A a;

  //getters
  //setters
}


I think you can accomplish this by making a @OneToOne relationship or a @OneToMany and point the table name like this

  @Id @OneToOne
  @JoinColumn(name = "id")
  private A a;
0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜