ASP.NET oracle 语句在执行更新的时候没有任何反映不知道咱回事？

string logip = Request.UserHostAddress;
        DateTime now = DateTime.Now;  //注册时间
        string time = now.Year.ToString().Trim() + "-" + now.Month.ToString().Trim() + "-" + now.Day.ToString().Trim() + " " + now.Hour.ToString().Trim() + ":" + now.Minute.ToString() + ":" + now.Second.ToString();        OracleConnection con = OraDBHelper.init();
        try
        {
            string sql2 = "update userinfo set endlogintime=to_date('" + time + "','yyyy-mm-dd hh24-mi:ss'),endloginIP='" + logip + "',lgoinnum=lgoinnum+1 where username='godlove'";
            OracleCommand daset = new OracleCommand(sql2,con);
            int i = Convert.ToInt32(daset.ExecuteNonQuery());
            if (i != 0)
            {
                Response.Write("ok");
            }
            else
            {
                Response.Write("error");
            }
        }
        catch (Exception e)
        {
            throw new Exception(e.Message.ToString());
        }
        finally
        {
            con.Close();
        }