如何拥有一个复合 id，其中字段在多个嵌入式类中可用

Question

The composite key for my table is userid, orderno, orderstatus.

Entity class is

@Entity
public class OrTest implements java.io.Serializable {

  private UserInfo user;   //UserInfo is embedded class having userid
  private OrderInfo order; // OrderInfo is embedded class having order
  private Status  status;  //Status is embedded class having orderstatus
  //Contains other misc info

}

How to use embeddedid in this scenario where my actual composite key fields are split across multiple embedded classes.

Answer 1

You can have EmbeddedId class contain all the 3 keys. like below

public class OrTextPk implements Serializable{
     @Column(name="userId")
     public String userId;
     @Column(name="orderNo")
     public String orderNo'
     @Column(name="orderStatus")
     public String orderStatus;
}

Now, in the OrText class you can do the following.

@Entity
public class OrTest implements java.io.Serializable {

  @EmbeddedId
  private OrTextPk id;

  @OneToOne(fetch=FetchType.LAZY)
  @JoinColumn(name="userId")
  private UserInfo user;   //UserInfo is embedded class having userid
  .
  .
  . 
  so on...
}

Answer 2

In addition to the solution posted by @Zeus, You only need to do minor change in following way.

Composite PK

public class OrTextPk implements Serializable{
 public String userId;
 @Column(name="orderNo")
 public String orderNo'
 @Column(name="orderStatus")
 public String orderStatus;
}

Main entity class

@Entity 
public class OrTest implements java.io.Serializable {
 @EmbeddedId
 private OrTextPk id;

 @OneToOne(fetch = FetchType.LAZY)
 // Note: it will help to map value of userId (UserInfo) to Pk object
 @MapsId("userId")  
 @JoinColumn(name = "userId")
 private UserInfo user;   //UserInfo is embedded class having userid
 .
      .
      .
 so on...
}

Now, on setting New/Persisted object of UserInfo (user), value of userId of UserInfo object will be assigned to userId of OrTextPk while persisting OrTest object.