How to prevent NULL entry in UPDATE operation using CRUD Repository? - spring

Question

Consider the following Events:-
CREATE User [id=1, name=Ram, city=Delhi, email=abc#gmail.com, phone=12345]
UPDATE User [id=1, city=Mumbai, phone=56789]
For CREATE operation, this is what is stored in the database:-
[id=1, name=Ram, city=Delhi, email=abc#gmail.com, phone=12345]
However, when I perform the UPDATE operation, fields which are not updated becomes null
[id=1, name=null, city=Mumbai, email=null, phone=56789]
Now, my question is that how do I prevent name and email from becoming NULL ??
Here is the code snippet :-
Entity Class:-
#Entity
public class User {
#Id
private Integer id;
private String name;
private String city;
private String email;
private String phone;
//Setters and Getters
}
Repository:-
import org.springframework.data.repository.CrudRepository;
import com.therealdanvega.domain.User;
public interface UserRepository extends CrudRepository<User, Integer>{
}
Application Class :-
#SpringBootApplication
public class JsontodbApplication implements CommandLineRunner {
#Autowired
private UserRepository userRepo;
public static void main(String[] args) {
SpringApplication.run(JsontodbApplication.class, args);
}
#Override
public void run(String... args) throws Exception {
/* CREATE USER */
userRepo.save(createUser());
/* UPDATE USER */
userRepo.save(updateUser());
System.out.println(userRepo.findOne(1));
}
public User createUser() {
User user = new User();
user.setId(1);
user.setName("Ram");
user.setCity("Delhi");
user.setEmail("abc#gmail.com");
user.setPhone("12345");
return user;
}
public User updateUser() {
User user = new User();
user.setId(1);
user.setCity("Mumbai");
user.setPhone("56789");
return user;
}
}

Answer 1

Your code doesn't work like you think it does. For Spring it is actually something like that :
Take new object User with id = 1 , name = Ram ... and put it into that base.
Take new object User with id = 1 , city = Mumbai ... and put it into that base.
Spring Repository works like that, if you save object with NULL id, it will add it. If you save object with given id it will update EVERY value that has changed. So for spring you actually update every field, some for new value and most of them for NULLs. MORE INFO
You should get your object which is return by first save function, and update it again. Like that :
#SpringBootApplication
public class JsontodbApplication implements CommandLineRunner {
#Autowired
private UserRepository userRepo;
public static void main(String[] args) {
SpringApplication.run(JsontodbApplication.class, args);
}
#Override
public void run(String... args) throws Exception {
/* CREATE USER */
User user = userRepo.save(createUser(new User()));
/* UPDATE USER */
userRepo.save(updateUser(user));
System.out.println(userRepo.findOne(1));
}
public User createUser(User user) {
user.setName("Ram");
user.setCity("Delhi");
user.setEmail("abc#gmail.com");
user.setPhone("12345");
return user;
}
public User updateUser(User user) {
user.setCity("Mumbai");
user.setPhone("56789");
return user;
}
}