how to make a composite primary key (java persistence annotation)

Question

How to make it so that the table user_roles defines the two columns (userID, roleID) as a composite primary key. should be easy, just can\'t remember/find.

In

Answer 1

I had the same Problem with the primary keys. I also knew the solution with the @Embeddable and @EmbeddedId Class. But i wanted just the simple solution with the annotations.

Well i found enlightenment through this article: http://www.vaannila.com/hibernate/hibernate-example/hibernate-mapping-many-to-many-using-annotations-1.html

and here is the magic:

this generates a primary key on the join table:

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name="classA_classB")
private Set classesA;

this dosn't generate a primary key on the join table:

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name="classA_classB")
private List classesA;

at least in my enviroment

Note that the difference is using Set or List