[hibernate-dev] Embedded Composite Identifiers

[Gunnar Morling]

FWIW, that's one of the mapping patterns I always found awkward, so +1 for
deprecating it from me.

What would be the strategy, though? Deprecate in 5 and remove in 6?

2015-08-03 17:46 GMT+02:00 Sanne Grinovero <sanne at hibernate.org>:

> I remember loving this feature.
> Composite keys are very common in databases I worked with, while
> loading by ids seems to be quite uncommon in my coding style as I
> don't remember knowing how to do that, nor that this ignorance ever
> bothered me :)
>
> +1 anyway, that's just to give some perspective.
>
> On 3 August 2015 at 16:36, Steve Ebersole <steve at hibernate.org> wrote:
> > Here is what I proposes in the documentation in the section discussing
> > composite identifiers:
> >
> >
> > <note>
> >     <para>
> >         Technically a composite identifier can be made up of just a
> > single persistent attribute.
> >     </para>
> >     <para>
> >         The restriction that a composite identifier has to be
> > represented by a "primary key class" is
> >         a JPA restriction.  Hibernate does allow composite identifiers
> > to be defined without a
> >         "primary key class", but use of that modeling technique is
> > deprecated and not discussed here.
> >     </para>
> > </note>
> >
> >
> >
> >
> > On Mon, Aug 3, 2015 at 10:30 AM Steve Ebersole <steve at hibernate.org>
> wrote:
> >
> >> I am thinking we should start to soft-deprecate[1] the historical
> feature
> >> of embedded composite identifiers.  This is the feature that allowed an
> >> entity to define a composite identifier without any kind of "pk class"
> >> (EmbeddedId/IdClass):
> >>
> >> @Entity
> >> public class MyEntity {
> >>     @Id
> >>     public Integer key1;
> >>     @Id
> >>     public Integer key2;
> >>    ...
> >> }
> >>
> >> The you'd always have to instantiate the entity to deal with its
> >> identifier.  For example, to load such an entity:
> >>
> >> MyEntity id = new MyEntity(1,2);
> >> MyEntity it = session.get( MyEntity.class, id );
> >>
> >>  Between EmbeddedId and IdClass there are better alternatives to
> document.
> >>
> >> Thoughts?
> >>
> >> [1] - By "soft-deprecate" I mean remove discussion of it from the
> >> documentation, and don't really push it.
> >>
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