[hibernate-dev] Can a transient attribute be overridden to be persistent in a subclass?

[andrea boriero]

Hi Gail,

based on my understanding of Section 2.2  it seems that it should not be
portable, but I think that it would be nice for Hibernate to support the
feature.

On Thu, 9 Jul 2020 at 17:40, Gail Badner <gbadner at redhat.com> wrote:

> Hi Christian,
>
> It actually does work already.
>
> I was just trying to get answers to the questions at the end of my email.
>
> > Would overriding a transient attribute be portable? If not, is that
> something Hibernate would/should support?
>
> If the answer is "yes" to either of those, I'll add a test case to the test
> suite.
>
> Thanks,
> Gail
>
> On Thu, Jul 9, 2020 at 12:47 AM Christian Beikov <
> christian.beikov at gmail.com>
> wrote:
>
> > I agree, this should work. Do you have a JIRA ticket describing what the
> > problem is?
> >
> > Am 09.07.2020 um 02:42 schrieb Gail Badner:
> > > I *think* the following is valid, but I need confirmation. This mapping
> > > does seem to work for Hibernate.
> > >
> > > A transient attribute, Employee#title, gets overridden as a persistent
> > > attribute, Editor#title, stored in a column named "e_title".
> > >
> > > Writer#title is also transient, but Writer#group uses the same
> "e_title"
> > > column as a foreign key. That foreign key value is used to populate
> > > Writer#title.
> > >
> > > @Entity
> > > @Table(name="Employee")
> > > @Inheritance(strategy = InheritanceType.SINGLE_TABLE)
> > > @DiscriminatorColumn(name="department")
> > > public abstract class Employee {
> > >      private String name;
> > >      private String title;
> > >
> > >      @Id
> > >      public String getName() {
> > >          return name;
> > >      }
> > >
> > >      @Transient
> > >      public String getTitle() {
> > >          return title;
> > >      }
> > >
> > >      protected void setName(String name) {
> > >          this.name = name;
> > >      }
> > >
> > >      protected void setTitle(String title) {
> > >          this.title = title;
> > >      }
> > > }
> > >
> > > @Entity
> > > public class Editor extends Employee {
> > >      @Column(name = "e_title")
> > >      public String getTitle() {
> > >          return super.getTitle();
> > >      }
> > >
> > >      public void setTitle(String title) {
> > >          super.setTitle( title );
> > >      }
> > > }
> > >
> > > @Entity
> > > public class Writer extends Employee {
> > >      private Group group;
> > >
> > >      @ManyToOne(optional = false)
> > >      @JoinColumn(name = "e_title")
> > >      public Group getGroup() {
> > >          return group;
> > >      }
> > >
> > >      public void setGroup(Group group) {
> > >          this.group = group;
> > >          setTitle( group.getName() );
> > >      }
> > > }
> > >
> > > In 4.2, the above mapping worked with Employee#title being persistent,
> > but
> > > does not work in 5.3.
> > >
> > > Section 2.2 Persistent Fields and Properties of the spec says:
> > >
> > > "Entity subclasses may override the property accessor methods. However,
> > > portable applications must not override the object/relational mapping
> > > metadata that applies to the persistent fields or properties of entity
> > > superclasses."
> > >
> > > Would overriding a transient attribute be portable? If not, is that
> > > something Hibernate would/should support?
> > >
> > > Thanks,
> > > Gail
> > > _______________________________________________
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> >
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