/// <summary>
        /// 更新DataSet
        /// </summary>
        /// <param name="cnnStr">连接串</param>
        /// <param name="ds">要更新的DataSet</param>
        /// <param name="sqlBefore">在更新之前执行的SQL</param>
        /// <param name="sqlAfter">在更新之后执行的SQL</param>
        public static void Update(string connectionString, DataSet ds, string sqlBefore, string sqlAfter)
        {
            SqlDataAdapter da = null;
            SqlTransaction tran = null;
            using(SqlConnection cnn = new SqlConnection(connectionString))
            {
                cnn.Open();
                tran = cnn.BeginTransaction();

                if(!string.IsNullOrEmpty(sqlBefore.Trim()))   //执行更新前的SQL
                {
                    using(SqlCommand cmd = new SqlCommand(sqlBefore.Trim(), cnn, tran))
                    {
                        cmd.ExecuteNonQuery();
                    }
                }
                foreach(DataTable dt in ds.Tables)
                {
                    string sql = string.Format("SELECT * FROM {0} WHERE 1 = 0 ", dt.TableName);
                    if(dt.ExtendedProperties["SELECT"] != null)
                    {
                        sql = dt.ExtendedProperties["SELECT"].ToString();
                    }
                    da = new SqlDataAdapter();
                    SqlCommandBuilder cb = new SqlCommandBuilder(da);
                    da.SelectCommand = new SqlCommand(sql, cnn, tran);
                    da.Update(ds, dt.TableName);
                }
                if(!string.IsNullOrEmpty(sqlAfter.Trim()))   //执行更新后的SQL
                {
                    using(SqlCommand cmd = new SqlCommand(sqlAfter.Trim(), cnn, tran))
                    {
                        cmd.ExecuteNonQuery();
                    }
                }
                tran.Commit();
            }
        }

        /// <summary>
        /// 更新DataSet
        /// </summary>
        /// <param name="cnnStr"></param>
        /// <param name="tableName"></param>
        /// <param name="ds"></param>
        public static void Update(string connectionString, DataSet ds)
        {
            Update(connectionString, ds, string.Empty, string.Empty);
        }