OneToOne or OneToMany?

btownsend · **Joined:** Wed Jul 19, 2006 9:03 pm **Posts:** 1

Greetings,

I'm new to Hibernate so I may be approaching this problem completely wrong. The relationship I want to model is described below - ClassA contains exactly 3 references to ClassB:

Code:

Class A {
  ClassB x;
  ClassB y;
  ClassB z;
}

Class B {
  ClassA a;
}

I don't think I can implement this as @OneToOne because x,y, and z would all be related to a. But, I don't know how to make this a @OneToMany either since x,y and z are not part of a collection.

Is this proper technique for modeling such a relationship to convert my x, y, and z elements into a collection of ClassB? Or is there a way I can maintain an explicitly bounded multiplicity (i.e. 1 to 3 instead of just 1 to many)?

Thanks!

emmanuel · **Posted:** Mon Jul 24, 2006 5:02 pm

Let's assume that x is the birirectional version of a, and y and z anre unrelated

Code:

Class A {
  @ManyToOne @JoinColumn(name="x_b_id")
  ClassB x;
  @ManyToOne @JoinColumn(name="y_b_id")
  ClassB y;
  @ManyToOne @JoinColumn(name="z_b_id")
  ClassB z;
}

Class B {
  @OneToOne(mappedBy="x"
  ClassA a;
} 