[hibernate-dev] Embedded Composite Identifiers

[Sanne Grinovero]

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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