[hibernate-issues] [Hibernate-JIRA] Issue Comment Edited: (HHH-6911) Write DiscriminatorValue to DiscriminatorColumn when combined with InheritanceType#JOINED

[k reid (JIRA)]

    [ https://hibernate.onjira.com/browse/HHH-6911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=45816#comment-45816 ] 

k reid edited comment on HHH-6911 at 3/3/12 5:23 PM:
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Hmmm...guess I didn't search the forums well enough before opening a ticket for this same issue.  Hibernate supports this functionality using the xml descriptor but not using annotations.  Please review HHH-7144 and mark as duplicate if necessary.

Thanks.

      was (Author: kor):
    Hmmm...guess I didn't search the forums well enough before opening HHH-7144 for this same issue.  Please review it and mark as duplicate if necessary.

Thanks.
  
> Write DiscriminatorValue to DiscriminatorColumn when combined with InheritanceType#JOINED
> -----------------------------------------------------------------------------------------
>
>                 Key: HHH-6911
>                 URL: https://hibernate.onjira.com/browse/HHH-6911
>             Project: Hibernate ORM
>          Issue Type: Improvement
>          Components: annotations, metamodel
>            Reporter: Steve Ebersole
>            Priority: Minor
>              Labels: jpa2
>
> The JPA spec states that {{DiscriminatorColumn}} can be used in conjunction with JOINED inheritence.  The only section that seems to deal with this combination is _11.1.10 DiscriminatorColumn Annotation_ where it says
> {quote}
> For the SINGLE_TABLE mapping strategy, and typically also for the JOINED strategy, the persistence
> provider will use a type discriminator column. The DiscriminatorColumn annotation is used to
> define the discriminator column for the SINGLE_TABLE and JOINED inheritance mapping strategies.
> {quote}
> Apparently this is meant to imply that even if providers do not need/use the discriminator for concrete class resolution (reading) they are still expected to write it out to the database.  Dunno, thats just what we have been told :)
> Anyway, like I said, Hibernate itself does not need the discriminator column/value to interpret the concrete classes.  However, in the interest of portability we certainly *could* write it out.  
> Longer term we could *possibly* even use the DiscriminatorColumn/DiscriminatorValue (if present) instead of the SQL CASE statement thing we do now.
> See HHH-4358 for the origins of this request...

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