Spring JPA CrudRepository save(Entity) is returning 0 in id field

Question

I am adding spring JPA/Hibernate 5 to an old project. I am running CrudRepository .save(Entity) method against a Mainframe/DB2 table. The row is inserted just fine, but returnedEntity.getIdColumn() has 0 in it. I really need the ID for further processing. Could somebody please help? Thank you very much!

@Entity
Table(name="MY_TABLE")
public class myClass {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="ID_COLUMN")
private Long idColumn;
...

}

Identity is the only strategy type that worked. Here is the Service class:

@Transactional
public Entiry insertEntity(Entity originalEntity) {
   return MyRepository.save(originalEntity);
}
Runner class:
Entity originalEntity = createEntity();
Entity returnedEntity = ServiceClass.insertEntity(originalEntity);
System.out.println(originalEntity.getIdColumn());
System.out.println(returnedEntity.getIdColumn());

Andrew Preizner · Answer 1 · 2018-09-29T13:00:31.630

3

My guess is that you're trying to get an ID before your transaction was flushed to DB. Thus JPA doesn't know what id will be assigned and returns 0.

Edited: I'd recommend to have something like this:

@Transactional
public Entity save( .....) {
   //some code
   repository.save(entity);
   //some code
   return entity;
}

Transaction will be flushed at the end of this method and entity which will be returned from it should have a real id.

edited Sep 29 '18 at 13:00

answered Sep 29 '18 at 01:49

Andrew Preizner

254
1
5

Thank you, Andrew. saveAndFlush() of JpaRepository did not help. Is there another way? – Elena Sep 29 '18 at 02:24
you're welcome) Is the method where you call save transactional? – Andrew Preizner Sep 29 '18 at 02:46
If it's transactional - data from hibernate session may not be flushed to DB till the end of this method. – Andrew Preizner Sep 29 '18 at 02:54
OK, I removed @Transactional and still having no luck. Do I have any options how to get the Id, or my efforts are doomed? :( Thank you – Elena Sep 29 '18 at 03:04
So, I tried exactly how you have it, but still got 0. Your version sounds like I would return the original Entity in hope JPA will update it. All other posts suggest that JPA returns a new, updated object. So, I added my version of the code above with interrogating the original Entity object as well as the returned one. Both return 0 – Elena Sep 29 '18 at 15:12
hm...interesting. What about Runner class, is the method which call insertEntity also Transactional? If yes, please add propagation level REQUIRES_NEW for the insertEntity method: @Transactional(propagation=Propagation.REQUIRES_NEW) – Andrew Preizner Sep 29 '18 at 17:09
For some reason it is complaining about propagation saying Cannot resolve method 'propagation'. Thank you – Elena Sep 30 '18 at 02:19
hm.. Do you mean inside the annotation or what do you mean by method 'propagation' ? – Andrew Preizner Oct 01 '18 at 22:40
Turns out I was using the wrong Transactinal. I switched to javax.persistance... and the error went away. The 0 returned value issue remains. From spring debug messages it looks like the transaction is commited before I Sysout it. So, I do not think it is my issue. For some reason DB2 does not return the true value. Somebody suggested using @Query, but it does not look it supports Insert. I am really stuck. :( – Elena Oct 02 '18 at 13:44

score 2 · Answer 2 · answered Oct 03 '18 at 02:03

2

Turned out my table had an id sequence generator already defined in the DB. So, after I changed it to generationType.SEQUENCE it worked nicely. @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "MY_TABLE_SEQ")

answered Oct 03 '18 at 02:03

Elena

61
1
4

score 1 · Answer 3 · answered May 25 '19 at 08:37

Recently, I've faced with similar issue.

In my case, the new entity has been passed from UI and ID was 0 instead of NULL (since the type of ID was primitive on Java side). Therefore Hibernate didn't use right save strategy.

Eventually, I changed the type from long to Long and it helped:
private long id;
private Long id;

Also update method was changed from:

@PutMapping("/{id}")
public T update(@PathVariable ID id, @Valid @RequestBody T entity) {
    this.getService().update(entity);
    return entity;
}

to:

@PutMapping("/{id}")
public T update(@PathVariable ID id, @Valid @RequestBody T entity) {
    return this.getService().update(entity);
}

P.S.: When entity ID was 0, Hibernate was using merge strategy, however, it should persist strategy for new Entities instead (link for implementation of save method).

Spring JPA CrudRepository save(Entity) is returning 0 in id field

3 Answers3