Question about associatoin class mapping!

xinhua · **Joined:** Sat Nov 05, 2005 8:59 pm **Posts:** 16

Hello,
Suppose there is an many to many association between Class A and Class B.
Class A_B is their association class. Now i have following code with mapping annotation:

Class A

Code:

@Entity(access=AccessType.FIELD)
public class A implements Serializable {
   
   @OneToMany( mappedBy="role_a")
   private List<A_B> a_B = new ArrayList( );
   
   @Id(generate=GeneratorType.IDENTITY)
   public long id;
        .....

Class B

Code:

@Entity(access=AccessType.FIELD)
public class B implements Serializable {
   
       @OneToMany(mappedBy="role_b")
   private A_B a_B = null;
   
   @Id(generate=GeneratorType.IDENTITY)
   public long id;
   
        .....

Class A_B

Code:

@Entity(access=AccessType.FIELD)
public class A_B implements Serializable {
   
   @ManyToOne(cascade=CascadeType.All)
   private A role_a = new AA();
   
   @ManyToOne(cascade=CascadeType.All)
   private B role_b = new B();
        .......

How can i make the fields "role_b" and "role_a" in Class A_B to be composite primary key????

any help would be appreciated

emmanuel · **Posted:** Thu May 25, 2006 3:02 pm

use a composite key mapping the ids and define a @ManyToOne on the same underlying columns beiing insert=false, update=false