Re: Hibernate Annotations

From:

Simon <count.numbers@web.de>

Newsgroups:

comp.lang.java.programmer,de.comp.lang.java

Date:

Wed, 05 Aug 2009 17:03:00 +0200

Message-ID:

<7dtl98F2dodurU1@mid.dfncis.de>

I'm also not an expert, but since noone else replied, I will give it a try.

@Entity
@IdClass(value = MyPrimaryKey.class)
@Table(name = "MYSCEMA.MYTABLE")
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
public class MyTable implements Serializable
{
@Id
private MyPrimaryKey id;

Shouldn't this be replaced by

   @Id
    private Long compositeId1;

   @Id
    private Boolean compositeId2;

     @Column(name = "COLUMN3")
    private String column3;

    @Column(name = "COLUMN4")
    private String column4;

    @Column(name = "COLUMN5")
    private String column5;

[..]
}

@Embeddable
public class MyPrimaryKey implements Serializable
{

    @Column(name = "COMPOSITE_ID1_WHICH_IS_ALSO_A_FK")
    private Long compositeId1;

    @Column(name = "COMPOSITE_ID2")
    private Boolean compositeId2;
[..]
}

As far as I know, you don't use the class referenced by @IdClass as a
key, but you rather take all its properties as keys, each one annotated
with @Id. Otherwise I wouldn't see why it would help to specify an
@IdClass if the @Id is actually an instance of this class.

I never tried @Embeddable as a key, but if it works I would assume you
don't need the @IdClass annotation. What happens if you omit it?

Cheers,
Simon

f'Up2 c.l.j.p