Hibernate Mapping JPA Collections

Question

I want to do a pretty simple thing but can't get it to work.

I have ab entity Game and an Entity Player. Every Game should have two foreign keys from Players. And it works, but there is one catch: I cant assign the same foreign key from Player to multiple Game-entities. Where is this constraint coming from, and how can I tell him to not do that?

I'm using Hibernate and JPA. My persistence.xml looks like this:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence" version="1.0">
<persistence-unit name="PlayerService" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
  <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
  <property name="hibernate.connection.driver_class" value="org.postgresql.Driver"/>
  <property name="hibernate.connection.username" value="********"/>
  <property name="hibernate.connection.password" value="********"/>
  <property name="hibernate.connection.url" value="jdbc:postgresql://********"/>          
  <property name="hibernate.hbm2ddl.auto" value="create"/>        
</properties>
</persistence-unit>
</persistence>

I'm getting the entitymanager per:

util = new JPAUtil();
emf = Persistence.createEntityManagerFactory("PlayerService");
em = emf.createEntityManager();
em.getTransaction().begin();

in my Games-Entity:

@ElementCollection(targetClass=Player.class)
private Collection<Player> player;

and there is Player-Entity.

Am I doing this entirely wrong?

---

@Entity
public class Game {

    @Id
    int gameid;

    @OneToMany(mappedBy="game")
    private Collection<TestPlayer> test;
}

@Entity
public class TestPlayer {

@Id
int id;

@ManyToOne
@JoinColumn(name="gameid")
private Game game;
}

Answer 1

I'll try an OneToMany relationship instead of ElementCollection .

I think that in an ElementCollection the elements ( Player ) belongs to the Game and therefore Hibernate doesn't let you assign it to multiple Games

in your Game Entity:

@OneToMany(mappedBy="game")
private Collection<Player> player;

in your Player entity:

@ManyToOne
@JoinColumn(name="game_id")
private Game game;

for reference: http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/entity.html#entity-mapping-association