[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-7138) Hibernate implements JPA @OneToMany collection versioning incorrectly

[Uli Bubenheimer (JIRA)]

    [ https://hibernate.onjira.com/browse/HHH-7138?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=45809#comment-45809 ] 

Uli Bubenheimer commented on HHH-7138:
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Steve, sorry to correct you, but Hibernate does NOT do what the spec says.

The relationship in my example is owned by the child entity, and NOT owned by the parent entity. The collection is a field of the parent entity. So when a child is added to the collection, it is not valid to change versions on the parent entity. Hibernate does not follow this rule.

This is the example from Section 2.10.2 of the JPA 2.0 spec ("Bidirectional ManyToOne / OneToMany Relationships"), which states explicitly that the child entity is considered the owner of the relationship.

I want to emphasize that this is not just a theoretical problem, and I assume that's why the JPA spec is so specific on this point. The default Hibernate behavior essentially prevents concurrent creation of any child entities in bidirectional one-to-many relationships.

> Hibernate implements JPA @OneToMany collection versioning incorrectly
> ---------------------------------------------------------------------
>
>                 Key: HHH-7138
>                 URL: https://hibernate.onjira.com/browse/HHH-7138
>             Project: Hibernate ORM
>          Issue Type: Bug
>    Affects Versions: 3.6.8, 4.1.0
>         Environment: Hibernate 4.1.0 or 3.6.8., SQL Server or H2 Database Engine
>            Reporter: Uli Bubenheimer
>         Attachments: H812NVersioningBug.zip
>
>
> Context: In my pure JPA-compliant app I have a bidirectional 1:n relationship expressed via a @ManyToOne foreign key on the child entity class, and a @OneToMany collection of children on the parent entity class. Both entity classes use optimistic locking via a @Version field.
> Problem: When I create a new child entity, and add the entity to the collection on the parent, the parent's version changes, causing OptimisticLockingException when concurrently creating child entities. As the parent is the non-owning side of the relationship, this violates the JPA spec.
> JPA 2.0 states the following (Section 3.4.2):
> bq.The version attribute is updated by the persistence provider runtime when the object is written to the database. *All non-relationship fields and properties and all relationships owned by the entity are included in version checks.*
> What the JPA spec says is reasonable, as the parent entity's associated DB record does not change at all in this case (besides the bad version increment).
> I am attaching a simple test case reproducing the problem.
> This was previously described here: http://stackoverflow.com/a/5259163
> It looks like no defect was created at the time.
> A workaround, as mentioned in the article, is to specify @OptimisticLock(exclude = true) on the @OneToMany collection field. However, this pollutes a pure JPA app and makes it non-portable.

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