Create two primary key (Also those are foreign key) from different class

Question

class A{
@id
int a;
}

enter code here

class B {
@id
int b;
}

A

a ====> primary key

B

b ====> primary key

C

a and b needs to be primary key for the table. Also a and b are foreign key

How to add a and b into the third table(C) as a primary key which also needs to be foreign key too?

Answer 1

You can use @EmbeddedId with @MapsId on to-one associations.

Examples can be found here, here and in the official documentation.