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I have two classes Foo and Bar . The tables in the database look like this: |Foo| |id : INT (PK) | bar_id : INT (PK, FK) | |Bar| |id : INT (PK) | Normally I would map it like this: @Entity public class Bar { @Id @Column(name = "id") private int id; @OneToMany private Set<Foo> foo; } @Entity public class Foo { @EmbeddedId private FooPK key; @MapsId("barId") @ManyToOne @JoinColumn(name = "bar_id", referencedColumnName = "id") private Bar bar; } @Embeddable public class FooPK { @Column(name = "id") private int id; @Column(name = "bar_id") private int barId; } However the id's in FooPK are loosely mapped and need to be connected manually. I would prefer a solution that maps using Objects in stead of loose ids. I tried the following but (of course) it didn't work, but I think it gives an idea of what I would like to achieve: @Entity public class Bar { @Id @Column(name = "id") private int id; @OneToMany private Set<Foo> foo; } @Entity public class Foo { @EmbeddedId private FooPK key; @MapsId("barId") @ManyToOne @JoinColumn(name = "bar_id", referencedColumnName = "id") @Access(AccessType.FIELD) private Bar getBar() { return key.getBar(); } } @Embeddable public class FooPK { @Column(name = "id") private int id; @Transient private Bar bar; //.... @Column(name = "bar_id") @Access(AccessType.PROPERTY) private int getBarId { return bar.getId(); } } Another problem with the latter solution is that the getBarId() method in FooPK needs to have a setBarId(Int) method. Setting the Object using the ID can be done by accessing the data access layer, however this (in my opinion) violates the separation of business/

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