How can I set foriegn key column in Spring JPA - jpa

Question

I am using Spring JPA and want to set value to a foreign key column. Here is my entities and repository.
#Entity
public class Device {
#NotEmpty
#Id
private String deviceId;
#ManyToOne
#JoinColumn(name="userId", referencedColumnName="userId", insertable=false, updatable=false)
#NotFound(action=NotFoundAction.IGNORE)
private User user;
//Getters and setters
}
#Entity
public class User(){
#Id
private String userId;
private String userName;
//Getters and setters
}
public interface DeviceRepository extends PagingAndSortingRepository {
}
public class DeviceServiceImpl implements DeviceService {
#Autowired
private DeviceRepository devRepos;
#Autowired
private UserRepository userRepos;
#Override
public void saveDevice(Device device, String userId) {
User user = null;
if (userId!=null) {
user = userRepos.findOne(userid);
device.setUser(user);
}
deviceRepos.save(device);
}
}
The user exists in Device table but userId column in the table does not set the value. Please help me to fix the problem.
EDIT:
I removed insertable and updatable from the annotation and now it works.
#JoinColumn(name="userId", referencedColumnName="userId")
Then, this means I have to get user of the device from the User table whenever I save a device?

Answer 1

Because you set insertable and updatable to false for the user property in your Device class , it will cause the persistence provider to ignore this column (Device.userId) when generating SQL INSERT and UPDATE statement.
Just change them to true or remove them as their default values are already true.
Update :
this means I have to get user of the device from the User table
whenever I save a device?
In pure JPA , if you know the ID of the user , you can use EntityManager#getReference(User.class , aUserId) to get an User instance without actually querying from DB . But in Spring Data JPA , it seems that this method is not supported out of the box.