Hi,

I am new to Hibernate & JPA and I decided to use Hibernate instead of Ibatis at may new project. But now a little worried about deadline.
I am reading hibernate jpa docs and it was awesome for simple mappings. But now get stuck with mapping TableC with 3 ManyToOne assosiated pk fields.

TableA
+ aId (pk)

TableB
+ bId (pk)

TableC
+ aId (pk)
+ old_bId (pk)
+ new_bId (pk)

Thanks for your advice.

The general pattern for something like that is:

- Create an @Embeddable class to hold all the raw types (3 ints, or 3 longs, or whatever your PK type is) named after the columns to keep things simple).
- Map it in your TableC entity class with @EmbeddedId.
- Map the two foreign key properties as you normally would, with @ManyToOne and @JoinColumn. Add "insertable=false" and "updatable=false" to the @JoinColumn mappings.
- Now you can refer to these non-insertable and non-updatable properties in the mappedBy attribute of your @OneToMany properties in TableA and TableB's entities.

The JPA2 way of doing it would be to use @MapsId annotations, but I've had problems with that and Hibernate so I just use the old method described above.