NHibernate Multi-Column DateType (When day month and year are in different columns)

MultiColDateTime.cs

#region Namespaces

using System;
using System.Data;

using NHibernate;
using NHibernate.SqlTypes;
using NHibernate.UserTypes;

#endregion

public class MultiColDateTime : IUserType
{
    public SqlType[] SqlTypes
    {
        get
        {
            return new[]
                   {
                       NHibernateUtil.Int32.SqlType, 
                       NHibernateUtil.Int32.SqlType, 
                       NHibernateUtil.Int32.SqlType
                   };
        }
    }

    public new bool Equals(object x, object y)
    {
        if (ReferenceEquals(x, y))
        {
            return true;
        }
        if (ReferenceEquals(null, x) || ReferenceEquals(null, y))
        {
            return false;
        }
        return x.Equals(y);
    }

    public int GetHashCode(object x)
    {
        return x == null ? typeof(DateTime).GetHashCode() + 473 : x.GetHashCode();
    }

    public object DeepCopy(object value)
    {
        return value;
    }

    public object Replace(object original, object target, object owner)
    {
        return original;
    }

    public object Assemble(object cached, object owner)
    {
        return cached;
    }

    public object Disassemble(object value)
    {
        return value;
    }

    public Type ReturnedType
    {
        get
        {
            return typeof(DateTime);
        }
    }

    public bool IsMutable
    {
        get
        {
            return false;
        }
    }

    public object NullSafeGet(IDataReader rs, string[] names, object owner)
    {
        var day = (int)NHibernateUtil.Int32.NullSafeGet(rs, names[0]);
        var month = (int)NHibernateUtil.Int32.NullSafeGet(rs, names[1]);
        var year = (int)NHibernateUtil.Int32.NullSafeGet(rs, names[2]);

        if (day == 0 || month == 0 || year == 0)
        {
            return null;
        }

        return new DateTime(year, month, day);
    }

    public void NullSafeSet(IDbCommand cmd, object value, int index)
    {
        if (value == null)
        {
            ((IDataParameter)cmd.Parameters[index]).Value = DBNull.Value;
        }
        else
        {
            var dateTime = (DateTime)value;
            switch (index)
            {
                case 0:
                    ((IDataParameter)cmd.Parameters[index]).Value = dateTime.Date;
                    break;
                case 1:
                    ((IDataParameter)cmd.Parameters[index]).Value = dateTime.Month;
                    break;
                case 2:
                    ((IDataParameter)cmd.Parameters[index]).Value = dateTime.Year;
                    break;
            }
        }
    }
}