休眠单表中复合外键和主键的一对一映射 [英] Hibernate one to one mapping on composite foreign key and primary key in single table

问题描述

我有一个类别表，带有复合主键和外键.我的表结构就像

I have a Catagory table, with composite primary key and foreign key. My table structure is like

CREATE TABLE CATAGORY (
  CATAGORY_ID int(11) NOT NULL,
  CATAGORY_NAME varchar(50) DEFAULT NULL,
  VERSION int(11) NOT NULL,
  PARENT_ID  int(11) DEFAULT NULL,
  PRIMARY KEY (CATAGORY_ID,VERSION)
);

ALTER TABLE CATAGORY ADD CONSTRAINT FOREIGN KEY (PARENT_ID, VERSION) REFERENCES CATAGORY (CATAGORY_ID, VERSION); 

我想要一个像这样的 Catagory 类的 ORM 映射

and I want a ORM mapping with Catagory class like this

public class Catagory {
    @EmbeddedId
    private CatagoryPk pk ;
    @Column(name="CATAGORY_NAME")
    private String  catagoryName;

    private Catagory parentId;

    private List<Catagory> childs ;                 

}
@Embeddable
public class CatagoryPk {
    @Column(name="VERSION")
    private Integer version;
    @Column(name="CATEGORY_ID")
    private Integer catagoryId;
}

现在如何注释

private Catagory parentId;  
private List<Catagory> childs ;  

推荐答案

@JoinColumns({
    @JoinColumn(name="VERSION", referencedColumnName="VERSION"),
    @JoinColumn(name="PARENT_ID", referencedColumnName="CATAGORY_ID")
})
@ManyToOne
private Catagory parentId;

@OneToMany(mappedBy="parentId")
private List<Catagory> childs;  

或使用 @IdClass 而不是 @EmbeddableId 的版本(使用 Eclipselink 2.2.1 测试):

or version with @IdClass instead of @EmbeddableId (tested with Eclipselink 2.2.1):

public class CatagoryPk implements Serializable {

    private Integer version;
    private Integer catagoryId;

    public CatagoryPk() {
    }

    public CatagoryPk(Integer version, Integer catagoryId) {
        this.version = version;
        this.catagoryId = catagoryId;
    }
}

@Entity
@IdClass(CatagoryPk.class)
public class Catagory {
    @Column(name="VERSION")
    @Id private Integer version;
    @Column(name="CATAGORY_ID")
    @Id private Integer catagoryId;

    @ManyToOne
    @JoinColumns({
        @JoinColumn(name="VERSION", referencedColumnName="VERSION", insertable=false, updatable=false),
        @JoinColumn(name="PARENT_ID", referencedColumnName="CATAGORY_ID")
    })
    private Catagory parentId;
}

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