Hi,

Suppose:
class Person {
Long id;
Long version;
String name;
Set<Category> categories;
}

class Category {
Long id;
Long version;
String name;
}

Person has one-to-many association with Category, and both classes are specified to hibernate with versioning for optimistic locking.

Regarding to the CRUD operations;
Create and Read operations are not confusing, since "create" merely instantiate a new object and save it via hibernate and "read" merely loads the instance from DB via hibernate. No version checking etc..

Suppose this is a simple application working with query strings.

Update:
updatePerson?id=1&version=3&name=max&categories=1,4,5

updatePerson command:

Person person = new Person()
person.setId(1)
person.setVersion(3)
person.setName(max)

synchronize person.categories with the categories having Ids 1,4,5

Hibernate.saveOrUpdate(person)

It simply works. Since I havent hold the versions of the categories, I should omit version check on association (optimistic-locking attribute = false ?).

Is the code above a correct way to implement optimistic locking while updating ?

Delete:
deletePerson?id=3&version=5

deletePerson command:

If I have a one-to-many association

Person person = new Person()
person.setId(3)
person.setVersion(5)

Hibernate.delete(person)

It should work. Is above code a correct way to implement optimistic locking while deleting ?

What about many-to-many associations ? How to implement update and remove with them ?

Thanks in advance.

MB