@OneToMany and composite primary keys?

Question

I\'m using Hibernate with annotations (in spring), and I have an object which has an ordered, many-to-one relationship which a child object which has a composite primary key

Answer 1

Found this question searching for the answer to it's problem, but it's answers didn't solve my problem, because I was looking for @OneToMany which isn't as good of a fit for the table structure I was going after. @ElementCollection is the right fit in my case. One of the gotchas of it I believe though is that it looks at the entire row of relations as being unique, not just the rows id.

@Entity
public class ParentObject {
@Column(nullable=false, updatable=false)
@Id @GeneratedValue(generator="...")
private String id;

@ElementCollection
@CollectionTable( name = "chidren", joinColumns = @JoinColumn( name = "parent_id" ) )
private List attrs;

...
}

@Embeddable
public static class ObjectChild implements Serializable {
    @Column(nullable=false, updatable=false)
    private String parentId;

    @Column(nullable=false, updatable=false)
    private String name;

    @Column(nullable=false, updatable=false)
    private int pos;

    @Override
    public String toString() {
        return new Formatter().format("%s.%s[%d]", parentId, name, pos).toString();
    }

    ... getters and setters REQUIRED (at least they were for me)
}