using System;
using System.Collections.Generic;
using System.Text;
using NHibernate.Mapping.Attributes;
using Nullables.NHibernate;
using Nullables;
namespace NHDemo
{
    [NHibernate.Mapping.Attributes.Class(Table = "USERS")]
    public class User
    {
        private int logonID;
        private string userName;
        private string password;
        private string emailAddress;
        private DateTime lastLogon;


        public User()
        {
        }

        [NHibernate.Mapping.Attributes.Id(1,Column = "LoginId", Name = "LogonID", TypeType = typeof(Int32))]
        [NHibernate.Mapping.Attributes.Generator(2, Class = "assigned")]
         [Param(3, Name = "assigned")]
        public virtual int LogonID
        {
            get { return logonID; }
            set { logonID = value; }
        }
        [NHibernate.Mapping.Attributes.Property(Column = "Name", TypeType = typeof(String),Length = 40)]
        public virtual string UserName
        {
            get { return userName; }
            set { userName = value; }
        }
        [NHibernate.Mapping.Attributes.Property(Column = "Password", TypeType = typeof(String), Length = 20)]
        public virtual string Password
        {
            get { return password; }
            set { password = value; }
        }
        [NHibernate.Mapping.Attributes.Property(Column = "EmailAddress", TypeType = typeof(String), Length = 40)]
        public virtual string EmailAddress
        {
            get { return emailAddress; }
            set { emailAddress = value; }
        }
        [NHibernate.Mapping.Attributes.Property(Column = "LastLogon", TypeType = typeof(DateTime))]
        public virtual DateTime LastLogon
        {
            get { return lastLogon; }
            set { lastLogon = value; }
        }
       
    }
}

Configuration conf = new Configuration();
            conf.AddAssembly("NHDemo");
            NHibernate.Mapping.Attributes.HbmSerializer.Default.Serialize("", System.Reflection.Assembly.GetExecutingAssembly());
            conf.AddXmlFile("User.hbm.xml");
            ISessionFactory factory = conf.BuildSessionFactory();
            //cfg.AddXmlFile("User.hbm.xml");
            ISession session = factory.OpenSession();
            //User joseph = (User)session.Load(typeof(User),1);
            ITransaction transaction = session.BeginTransaction();
            NHDemo.User newUser = new NHDemo.User();
            newUser.LogonID = 2;
            newUser.UserName = "Joseph Cool";
            newUser.Password = "abc123";
            newUser.EmailAddress = "joe@cool.com";
            newUser.LastLogon = DateTime.Now;

            session.Save(newUser);
           
            // commit all of the changes to the DB and close the ISession
            transaction.Commit(); [b]//This is the place where I'm getting Exception[/b]
            session.Close();