nh-example.cs

using (var txn = session.BeginTransaction())
{
	try
	{
		session.SaveOrUpdate(entity);
		session.Flush(); // <-- is this even necessary? UPDATE... Not necessary, thanks! :)
		txn.Commit();
	}
	catch (HibernateException)
	{
		txn.Rollback();
		throw;
	}
}

Not necessary. Here's mine:

    private void WithinTransaction(Action action)
    {
        ITransaction transaction = Session.BeginTransaction();
        try
        {
            action();
            transaction.Commit();
        }
        catch (Exception e)
        {
            transaction.Rollback();
            throw;
        }
        finally
        {
            transaction.Dispose();
        }
    }

    public void Save(T entity)
    {
        WithinTransaction(() => Session.SaveOrUpdate(entity));
    }

@benhyr thanks!

Reposting my tweet here.

I spoke too soon. I believe it may be necessary if you've changed the session.FlushMode (I believe it's FlushMode.Auto by default). Otherwise, you may need to manually do the flush in certain cases (likely not if if you're using GUID or HighLow keys but I'm not positive on those)