Hi!

Why does one have to load objects first (via session) in order to manipulate them, if they are already loaded in memory (but the session was closed beforehand)?

Example:
//code omitted for brevity
Person p1 = new Person();
p1.Name = "Person One";
s.Save(p1);

Person p2 = new Person();
p2.Name = "Person Two";
s.Save(p2);
s.Close();

//this does not work!! (unless everything happens in the same session)
p1.Friends.Add(p2);

//this works
tx = ses.BeginTransaction();
p1 = s.Load(typeof(Person), 1);
p2 = s.Load(typeof(Person), 2);
p1.Friends.Add(p2);
tx.Commit();
s.Close();

So, the question, from the different angle is:

Why does a function like this does not work?
AddFriend(Person p, Person f) {
s = factory.Opensession();
tx = session.BeginTran();
p.Friends.Add(friend);
tx.Commit();
s.Close();

}

but this one works?
AddFriend(Person p, Person friendf) {
s = factory.Opensession();
tx = session.BeginTran();
s.load(typeof(Person)
p.Friends.Add(f);
tx.Commit();
s.Close();

}

What would be logical is maybe a call to s.SaveOrUpdate(p), since p's property (collection/Set/List) changed...

Thanks for any clarifications on the subject.

Miha

If your Friends collection is lazy-loaded, the Person who has the collection needs to be associated with a session, otherwise lazy-loading doesn't work.

If the Person is disconnected and you want to add some friends, you have to associate the Person with a session with ISession.Lock(person, LockMode.None).

martijnb,

I have not specified lazy-loading (it defaults to false, right?). I presumed that if I have an object, and if I want to change this documents properties, that it is not necessary that it is loaded first (since the object has an ID anyway).

So, manipulating an object and saving it (without loading it first) would seem to work, but it does not.

Well, I guess that's just how it is, right? :)

Thanks,
Miha.

Your first example will work if you add a s.Update(p) before the call to commit. Otherwise the second session doesn't know about your object at all, so it won't persist any changes.