How to use hibernate @DynamicUpdate with spring data jpa?

Question

I am using spring data-jpa. I want update only one column.

My repository is;

public interface UserRepository extends JpaRepository<User,Long> {
}

my Service is;

public User save(User user) {
    return userRepository.save(user);
}

my Entity;

@Entity
@DynamicUpdate(true)
public class User implements Serializable {
    // column definitions, etc.
}

How can I update only one column in User?

Answer 1

First of all I want to explain why @DynamicUpdate is not working for you. So I should notice how @DynamicUpdate works:

The @DynamicUpdate annotation is used to specify that the UPDATE SQL statement should be generated whenever an entity is modified. By default, Hibernate uses a cached UPDATE statement that sets all table columns. When the entity is annotated with the @DynamicUpdate annotation, the PreparedStatement is going to include only the columns whose values have been changed.(more details)

For example assume that User has a property called name.

So if for the first time you saved user with a defined name, now you are passing null as the value @DynamicUpdate will assume it as a change and trying to update name to null.

First solution:

As the first solution, if you want @DynamicUpdate works, first you should fill all other User properties with old values, then you can save it.

Pros: The generated SQL query just updates the property you want.

Cons: Hibernate has to generate the corresponding SQL string each time and there is thus a performance cost on the Hibernate side.

Second solution:

You can update User with custom query:

@Modifying
@Query("UPDATE User SET name=(:name) WHERE id=(:id)")
public void updateName(@Param("name")String name, @Param("id")Long id);

Third solution:

As the last solution I can suggest you to use updatable = false. This will fill the property on the very first moment the entity inserted.

  @Column(name = "create_date", nullable = false, updatable = false)
    private Instant createDate;