Versioning with Timestamp

Hibernate ORM
1

I have taken a step back from creating my onw UserVersionType for now and I’m looking in more detail at the out of the box options (number / date). I have number working as I would expect - sets version to 0 on initial insert, increments automatically on update, doesn’t increment or get in the way updating with no change.

I wanted to look at using Date and essentially modified my working code sample from Long to Date. This does not work and I was wondering if anyone can help me ?

I am using 5.3.6.Final (with Spring)

I have this entity

Entity
Table (name=“Names”)
public class Names implements Serializable {

private static final long serialVersionUID = 1L;

private Long id;
private String name;
private Date version;

Id
Column(name=“id”, nullable=false)
public Long getId() {
return id;
}
public void setId(Long id) {
this.id= id;
}

Column(name=“NAME”, length=100)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

Version
public Date getVersion() {
return version;
}

public void setVersion(Date version) {
this.version = version;
}
}

I have this simple test

Test
public void test_1 () {

Names n = new Names ();

//1st record
n.setId(1L);
n.setName(“John Doe”);

System.out.println("SAVE 1 BEFORE ");

 nameService.saveRuleOfEngagement(roE);

System.out.println("SAVE 1 AFTER ");

There is nothing of real interest in the service I don’t think ?

public void saveName(Names n) {
Session currentSession = sessionFactory.getCurrentSession();
currentSession.saveOrUpdate(n);
}

So this worked with version as a long but now fails on update. In fact it doesn’t try to update. So first run of test puts

1, “John Doe”, 2019-01-28 11:04:55.314

If I run the same again (with the same data or a changed name) I get

SAVE 1 BEFORE
Hibernate:
insert
into
“Names”
(“NAME”, version, “id”)
values
(?, ?, ?)
2019-01-28T11:07:27,008 [main] [WARN] [org.hibernate.engine.jdbc.spi.SqlExceptionHelper.logExceptions(129)] - SQL Error: 0, SQLState: 23505
2019-01-28T11:07:27,008 [main] [ERROR] [org.hibernate.engine.jdbc.spi.SqlExceptionHelper.logExceptions(131)] - ERROR: duplicate key value violates unique constraint “Names_pkey”
Detail: Key (“id”)=(1) already exists.

When it was using Long and working it was doing a select then an update ? Now it goes straight to insert and fails.

All the help, official and unofficial that I have seen implies this should work out of the box ? Is there something obvious I have done wrong ?

2

The issue is not due to the version but to using the same identifier.

Use generated identifiers and it will work just fine.

3

Okay thanks. One oddity I am finding though is that the datestamp version is updated on regardless of whether there is actually an update or not (I’ve tried via session.update and session.saveOrUpdate). Using a number this works nicely - the version is only updated if there is a change, but what I’m finding with date is that if the update is called the version is updated regardless of whether there is a change. Am I doing something wrong or would I need to add a check before deciding on whether to call update if I used the date version ?

4

Session.update is meant to reattaching entities, so it should always schedule an update. Normally, the SQL UPDATE is detected automatically by the dirty checking mechanism so you don’t need to do anything special.