Spring data JPA saveAndFlush and cannot get auto increment field

Question

I have object with @Id (primary key) and this is some business UIID field and I want another Long technical Id for some reasons but when saving the object I get null from getObjectId field:

@Id
private String id;

@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "object_id")
private Long objectId;

public Long getObjectId() {
    return objectId;
}

public void setObjectId(Long objectId) {
    this.objectId = objectId;
}

I have this storage class:

   interface MyObjectStorage extends JpaRepository<MyObject, String>

And this is how I save it:

 final MyObject saved = storage.saveAndFlush(toSave);
 saved.objectId is null here..

And in my MySQL db the objectId field is marked not null auto increment..

PS. And I don't want this objectId field to be used by JPA when findById is executed.

you can achieve with database sequence https://stackoverflow.com/questions/51633747/map-autoincrement-non-primary-key-in-hibernate — Mohamed Saligh, Dec 18 '19 at 09:35
But do I must to mark this field with @Id annotation ? I don't want JPA to use this field when findById is executed. The String id field must be used then.. — michealAtmi, Dec 18 '19 at 09:37
pls take a look at the answer for this post https://stackoverflow.com/questions/277630/hibernate-jpa-sequence-non-id — star67, Dec 18 '19 at 09:45
Does this answer your question? [Hibernate JPA Sequence (non-Id)](https://stackoverflow.com/questions/277630/hibernate-jpa-sequence-non-id) — star67, Dec 18 '19 at 09:47

score 0 · Accepted Answer · answered Dec 18 '19 at 11:26

Hibernate/JPA isn't able to automatically create a value for your non-id-properties. The @GeneratedValue annotation is only used in conjunction with @Id to create auto-numbers.

The solution (or work-around) suggested in this forum is to create a separate entity with a generated Id, something like this:

 @Entity
    public class GeneralSequenceNumber {
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      @Column(name = "object_id")
       private Long objectId;
    }

    @Entity 
    public class MyEntity {
      @Id ..
      private Long id;

      @OneToOne(...)
      private GeneralSequnceNumber myVal;
    }

Sandhya · Answer 2 · 2019-12-18T09:53:09.103

-1

try the following code @Id must be a type of Integer or Long

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "object_id")
private Long objectId;

private String id;

public Long getObjectId() {
    return objectId;
}

public void setObjectId(Long objectId) {
    this.objectId = objectId;
}

interface MyObjectStorage extends JpaRepository<MyObject, Long>

edited Dec 18 '19 at 09:53

answered Dec 18 '19 at 09:44

Sandhya

1
3

I can't, you removed @Id from id field – michealAtmi Dec 18 '19 at 09:50
@Id must be int or Long – Sandhya Dec 18 '19 at 09:52
Not it doesnt, when you have java UUID field then it is varchar column in db. And in Java u have new UUID() and while creating data object you do id = myObject.getId().getId().toString(); – michealAtmi Dec 18 '19 at 09:55
@michealAtmi Note that Hibernate is _perfectly_ happy to use real UUID columns if you have a database that is from the 21st century (no idea if MySQL is). – chrylis -cautiouslyoptimistic- Dec 18 '19 at 10:31

Spring data JPA saveAndFlush and cannot get auto increment field

2 Answers2