[FIXED] JPA, save relation without querying entities

Issue

I have this Entity representing a relation between two other entities.

I'd like to save the relation without having to get Role and Privilege before saving.

I'd like something like .save(roleId, privilegeId) so I don't have to hit the database before saving the relation.

Is it possible and how ?

Thanks

@Entity
@Table(name = "security_role_privilege")
public class RolePrivilege implements Serializable {

  private static final long serialVersionUID = -4788066966268187121L;

  @EmbeddedId protected RolePrivilegeId id;

  @ManyToOne
  @JoinColumn(name = "role_id", insertable = false, updatable = false)
  protected Role role;

  @ManyToOne
  @JoinColumn(name = "privilege_id", insertable = false, updatable = false)
  protected Privilege privilege;

  protected RolePrivilege() {}


  public RolePrivilege(Role role, Privilege privilege) {
    super();
    this.role = role;
    this.privilege = privilege;
    this.id = new RolePrivilegeId(role.getId(), privilege.getId());
    this.privilege.getRolePrivileges().add(this);
    this.role.getRolePrivileges().add(this);
  }

  public RolePrivilegeId getId() {
    return this.id;
  }

  public Role getRole() {
    return this.role;
  }

  public Privilege getPrivilege() {
    return this.privilege;
  }
}

This is the Spring Data JPA Repository for this entity

@Repository
public interface RolePrivilegeRepository extends JpaRepository<RolePrivilege, RolePrivilegeId> {}

Solution

With a raw EntityManager you can use em.getReference(Class<T> clazz, Object primaryKey) to fetch only a reference to the entity you wish to link, without actually fetching the data for the entity.

Answered By - Kayaman