[hibernate-dev] Embedded Composite Identifiers

[Steve Ebersole]

I more just mean from a documentation perspective.  I don't plan on
removing the feature itself so much.  Although I guess we can revisit that
when we rework annotation binding and finish up model binding in general

On Tue, Aug 4, 2015, 1:51 AM Gunnar Morling <gunnar at hibernate.org> wrote:

> 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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