复合主键JPA表示

Question

我很难在Hibernate中映射复合主键连接。下面是我的模式的简化图片。请注意，我不能更改架构。

简化模式

@Entity
@Table(name = "tree")
public class Tree implements Serializable {
   @EmbeddedId
   protected TreePK treePK;

  @OneToOne(mappedBy = "tree")
  private Activity activity;
}

@Embeddable
public class TreePK implements Serializable {
    @Column(name = "id")
    private Integer id;

    //this is a foreign key from the volume table
    @Column(name = "volume_id")
    private Integer volumeId;
}

@Entity
@Table(name = "volume")
public class Volume implements Serializable {
   @Id
   private Integer id;
}

@Entity
@Table(name = "activity")
public class Activity implements Serializable {
   @Id
   private Integer id;

   @JoinColumn(name = "tree_id", referencedColumnName = "id")    
   @OneToOne
   private Tree tree;
}

引用com.corp.activity.tree的referencedColumnNames(id)未映射到单个属性

如何在Hibernate中构建这样的关系？我必须映射到单个属性(id)，尽管主键是复合的。

Answer 1

Eclipselink和Hibernate都不能做到这一点。许多年前，OpenJPA是唯一能够做到这一点的JPA实现程序。