Please explain about insertable=false and updatable=false in reference to the JPA @Column annotation

Question

If a field is annotated insertable=false, updatable=false, doesn't it mean that you cannot insert value nor change the existing value? Why would you want to do that?

@Entity
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @OneToMany(mappedBy="person", cascade=CascadeType.ALL)
    private List<Address> addresses;
}

@Entity
public class Address {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @ManyToOne
    @JoinColumn(name="ADDRESS_FK")
    @Column(insertable=false, updatable=false)
    private Person person;
}

Answer 1

You would do that when the responsibility of creating/updating the related entity in question isn't in the current entity. E.g. you have a Person and an Address. You'd like to add insertable=false, updatable=false to the @OneToMany relationship with the Person entity in the Address entity, simply because it's not the responsibility of the Address entity to create or update a Person. It's the other way round.