[hibernate-dev] Embedded Composite Identifiers

[Steve Ebersole]

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.
>