I think a little empathy for Joe's frustration is in order. Joe I
think you should appologise to people you would have offended by
taking out your frustration on them.
I have also been on the receiving end of what initially seem to be
unhelpful answers but later on when I understood the issues better, I
find that one of the replies I had been frustrated with already
contained the answer to my question.
Even at this, there are still some questions I have on nhibernate and
on other forums where I have given up on getting a direct answer
saying "this is so and so" or "this was not designed to be used like
so try using it like so" or even "you idiot, what were you thinking,
that's not what that means but this is the correct meaning". This
happens even on paid support forums so its not just the OS community.
Bottom line is this Joe, when you've written a response in frustration
take a few deep breaths to think it over before pressing the send
button.
I'm also learning nhibernate so I may be able to answer your questions
at a level you'll understand. Sometimes the more experienced guys
communicate in very condensed language, and unless you already
understand the solution you may find it difficult understanding their
explanation.
With regards to the cascade option, from my (limited) experience when
cascade is used on a class property it specifies what should happen to
a transient instance of objects referred to by the entity when the
session is eventually flushed or a transaction committed.
eg
if you have a parent object which has a collection of child objects
and the child collection is defined with a cascade=save-update. If the
parent object was retrieved from the db/session and you add a child
object to the parents collection, when the session is flushed or (the)
transaction is committed the child object will be saved without having
to do a session.save on the child object.
void dothis()
{
ISession session = .....
ITransaction t = session.BeginTransaction();
var parent = session.Get<Parent>(10);
child = new child();
parent.addChild(child); // or
parent.children.add(child);
child.Parent = parent; // for bidirectionality
t.Commit(); // or session.flush();
// the child object
will be inserted although you did not
// explicitly save it
}
If the parent object is also new, you have to call session.save on the
parent object and all its children reachable by cascaded properties
will be saved as well.
void saveNewParentAndChildren()
{
var parent = new Parent();
var child = new Child();
parent.addChild(child);
child.Parent = parent;
var session = .... get your session
session.Save(parent);
session.Flush(); // this will insert
cascaded child objects as well
}
Another aspect which you seem to be missing is that you are referring
to TicketID in your object model. This is not what is intended. You
should not have to deal with the TicketID in your note class instead
you would be referring to the Ticket object instead.
Instead of having
class Note
{
long TicketID;
string Text;
}
what you should have is
class Note
{
Ticket ticket;
string text;
}
Your mapping is where you would specify the column to be used in the
Note table to store the ticket's id.
The third thing you seem to have trouble with is this issue of
managing of the references yourself. If you are connecting object
together nhibernate does not help you manage the object references on
newly created connections. i.e. if you have a parent object and want
to add a child object to it you will need to in YOUR code do
parent.addChild(child) and child.Parent = parent, if you want a
bidirectional association.
Does this help.
Jide
On Feb 4, 9:42 pm, Joe Brockhaus <[email protected]> wrote:
> no one is willing to address this, eh?
>
> must be too simple of a problem. but alas, it is not.
> the behavior I'm seeing is both inconsistent, and routinely unexpected given
> common sense.
>
> for more context, please
> see:http://groups.google.com/group/fluent-nhibernate/browse_thread/thread...
>
> yes, i'm using Fluent for my mappings.
> yes, I can get you the HBM if you absolutely need it.
> yes, i'm confident that my problems are both a consequence of not mapping
> Fluent correctly, and also correct mappings resulting in unexpected NHib
> behavior.
>
> one such issue that does not seem to differ regardless of how I map my
> entities:
> -- Does NHib require me to add entities to the Session in the order in which
> they need to be saved to correctly reference a one-to-many/many-to-one
> association? For instance, if I have a Ticket instance which has mapped an
> IList<Note> ... I'm seeing that if I add 3 Note instances, which have valid
> Ticket instances references and valid Note.TicketID values, to the Session
> BEFORE adding the Note.Ticket instance, then BeginTransaction().Commit ..
> NHib fails on insert (Note.TicketID is an invalid FK, oracle error, as the
> TicketID column has a FK constraint). If I add the Ticket first, the save
> works, but the Note instances in the cache are not updated with the TicketID
> generated in Oracle. The database has correct values, but this means that if
> I Load<Ticket>(ticketID) again, Ticket.Notes(0).TicketID, for instance, is
> still 0 -- the value it had BEFORE the transaction was committed.
>
> Thanks for your help ....
>
> ------
> Joe Brockhaus
> [email protected]
> ------------
>
>
>
> On Wed, Feb 2, 2011 at 7:14 PM, fel0niousmonk <[email protected]> wrote:
> > background:
> > -- the database is Oracle.
> > -- PKs for both tables (TICKETS, NOTES) are generated by sequences
> > (SEQ_TICKET_ID, SEQ_NOTE_ID)
> > -- Silverlight & RIA Services
>
> > question:
> > -- given the following, what should my mapping look like?
>
> > public class Ticket
> > {
> > [Key]
> > public int TicketID {get;set;}
>
> > [Include]
> > [Association("Ticket_Notes",
> > "TicketID",
> > "TicketID"]
> > public IList<Note> Notes = new List<Note>();
> > }
> > public class Note
> > {
> > [Key]
> > public int NoteID {get;set;}
>
> > [Include]
> > [Association("Note_Ticket",
> > "TicketID",
> > "TicketID",
> > IsForeignKey = true)]
> > public Ticket Ticket {get;set;}
> > public int TicketID {get;set;}
> > }- Hide quoted text -
>
> - Show quoted text -
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