/// <summary>

         /// 使用原生的SQL查询

         /// </summary>

         /// <param name="datetime"></param>

         /// <returns></returns>

         public IList<Customer> GetCustomersByDateTimeUsingSql(string datetime)

         {

             IList<Customer> resuCustomers = null;

             ISession session = _sessionManager.GetSession();

             ITransaction transaction = session.BeginTransaction();

             ;

             try

             {

                 //方式一：直接拼装SQL语句

                 //String sql = String.Format("select distinct CustomerAlias.* " +

                 //                           " from Customer CustomerAlias inner join [Order] " +

                 //                           " on CustomerAlias.CustomerId = [Order].CustomerId" +

                 //                           " where [Order].OrderDate >='{0}';", datetime);

                 ////用原生的SQL语句查询时，用AddEntity拼装实体类

                 //resuCustomers = session.CreateSQLQuery(sql).AddEntity("CustomerAlias", typeof(Customer)).List<Customer>();

                 //方式二：使用查询参数

                 String sqlusingParameter = String.Format("select distinct CustomerAlias.* " +

                                                          " from Customer CustomerAlias inner join [Order] " +

                                                          " on CustomerAlias.CustomerId = [Order].CustomerId" +

                                                          " where [Order].OrderDate >=:paraDatetime And CustomerAlias.Age=:paraAge;");

                 //用原生的SQL语句查询时，用AddEntity拼装实体类

                 resuCustomers = session.CreateSQLQuery(sqlusingParameter).AddEntity("CustomerAlias", typeof(Customer))

                     .SetString("paraDatetime", datetime)

                     .SetInt32("paraAge", )

                     .List<Customer>();

                 transaction.Commit();

             }

             catch (Exception)

             {

                 transaction.Rollback();

                 throw;

             }

             finally

             {

                 //如果已经打开了支持延迟，当外部用到延迟加载属性，

                 //session早已关闭，所以会抛出异常。

                 session.Close();

             }

             return resuCustomers;

         }