> So, if I have
>
> class Person {
> int id;
> String name;
> List<Car> cars;
> }
>
> class Person {
> int id;
> String name;
> }
Have you really two versions of class Person?
> And I have 3 tables
>
> person (
> id,
> name
> )
>
> car (
> id,
> name
> )
>
> person_x_car (
> person_id
> car_id
> )
>
> How is it that I go about
>
> 1) Updating a Person who has changes to their cars
There is no UPDATE statement to achieve this. You can DELETE all rows in
person_x_car and then INSERT the recent pairs (person_id, car_id), if
there are no dependencies on the table person_x_car. Otherwise, or in
case you want to log the changes, you have to identify the disjoined
respectively added cars and DELETE/INSERT the appropriate rows.
> 2) Deleting a Person and subsequently deleting the relevant rows in
> person_x_car
If your DBMS support DELETE ON CASCADE you can just delete the person row.
-- ALTER TABLE person_x_car DROP CONSTRAINT fk_person_x_car_person;
ALTER TABLE person_x_car
ADD CONSTRAINT fk_person_x_car_person FOREIGN KEY (person_id)
REFERENCES person (id) ON DELETE CASCADE;
Otherwise you have to iterate over the car list and delete each join
before deleting the person.
