Hibernate JPA ManyToOne composite key

Question

I'm trying to setup my entity to allow to pks. My database consist of two fields,

dealer_detail_id pk user_detail_id pk

Both join on id in corresponding tables.

I've tried this thus far without success.

@Embeddable
public class DealerUserPk implements Serializable {

    private Integer dealerDetail;
    private Integer userDetail;

DealerUser

@Embeddable
@Table(name = "dealer_user", schema = "account") 
public class DealerUser implements Serializable {

    @EmbeddedId
    private DealerUserPk id;

    @Id
    @ManyToOne
    @JoinColumn(name = "dealer_detail_id", referencedColumnName = "id")
    private DealerDetail dealerDetail;

    @Id
    @ManyToOne
    @JoinColumn(name = "user_detail_id", referencedColumnName = "id")
    private UserDetail userDetail;

DealerDetail

@Entity
@Table(name = "dealer_detail", schema = "account") 
public class DealerDetail implements Serializable {

    @Id
    private Integer id;

UserDetail

@Entity
@Table(name = "user_detail", schema = "account") 
public class UserDetail implements Serializable {

    @Id
    private Integer id;

Can anybody spot what I'm doing wrong?

Answer 1

Try this

 @Embeddable 
 public class DealerUserPk implements Serializable {

    @ManyToOne
    private DealerDetail dealerDetail;

    @ManyToOne
    private UserDetail userDetail;

    public void setDealerDetail(DealerDetail dealerDetail) {
      this.dealerDetail=dealerDetail;
    }

    public DealerDetail getDealerDetail(){
      return this.dealerDetail;
    }

    public void setUserDetail(UserDetail userDetail) {
      this.userDetail=userDetail;
    }

    public UserDetail getUserDetail() {
      return this.userDetail;
    }

 }

and

 @Entity
 @Table(name = "dealer_user")
 public class ProductItem {

    @Id 
    private DealerUserPk id= new DealerUserPk();

    // --- For bidirectional association---

    @SuppressWarnings("unused")
    @Column(name="dealer_detail_id", nullable=false, updatable=false, insertable=false)
    private Integer dealerDetail;

    @SuppressWarnings("unused")
    @Column(name="user_details_id", nullable=false, updatable=false, insertable=false)
    private Integer userDetail;

    // ---

    public void setDealerDetail(DealerDetail dealerDetail) {
      id.setDealerDetail(dealerDetail);
    }

    public DealerDetail getDealerDetail(){
      return id.getDealerDetail();
    }

    public void setUserDetail(UserDetail userDetail) {
      id.setUserDetail(userDetail);
    }

    public UserDetail getUserDetail() {
      return id.getUserDetail();
    }
  } 

Answer 2

This is correct:

@Embeddable
public class DealerUserPk implements Serializable {

    private Integer dealerDetail;
    private Integer userDetail;

1. But your DealerUser is annotated with embeddable it should be @Entity as you are using @Table annotation.

2. Need to add MapsId as it follows

    @Entity
    @Table(name = "dealer_user", schema = "account") 
     public class DealerUser implements Serializable {
   
   @EmbeddedId
   private DealerUserPk id;
   
   @MapsId("dealerDetail")
   @ManyToOne
   @JoinColumn(name = "dealer_detail_id", referencedColumnName = "id")
   private DealerDetail dealerDetail;
   
   @Id
   @MapsId("userDetail")
   @JoinColumn(name = "user_detail_id", referencedColumnName = "id")
   private UserDetail userDetail;
   

Try with that.