在資料庫批量產生不重複有序訂單號

在電子商務網站中，如果資料量大的話，經常容易產生重複訂單號。下面是我寫的一個產生不重複訂單號

的一個方法，根據當天時間和最大訂單來產生的，主鍵需要是遞增的。

 

class Program<br /> {<br /> /// <summary><br /> /// 鎖對象<br /> /// </summary><br /> private static object obj = new object();</p><p> /// <summary><br /> /// 當日最大訂單號<br /> /// </summary><br /> private static int maxOrder = 0;</p><p> /// <summary><br /> /// 當日時間<br /> /// </summary><br /> private static int TodayDay=DateTime.Now.Day;</p><p> static void Main(string[] args)<br /> {<br /> while (true)<br /> {<br /> Thread thread = new Thread(CreateOrder);<br /> thread.Start();<br /> //Thread.Sleep(1000);<br /> }<br /> //CreateOrder();<br /> }</p><p> /// <summary><br /> /// 產生16位訂單號<br /> /// </summary><br /> static void CreateOrder()<br /> {<br /> StringBuilder str = new StringBuilder();</p><p> str.Append("Or");//訂單開頭</p><p> str.Append(DateTime.Now.ToString("yyyyMMdd"));//訂單中間時間</p><p> lock (obj)<br /> {<br /> if (maxOrder == 0 || TodayDay != DateTime.Now.Day)<br /> {<br /> string Time = DateTime.Now.ToString("yyyy-MM-dd");// + " 00:00:00";<br /> string strSql = string.Format("select top 1 substring(OrderNo,11,6) from OrderTable where addtime between '{0}' and '{1}' order by id desc", Time + " 00:00:00", Time + " 23:59:59");//這句sql語句很重要<br /> using (SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=temp;Integrated Security=True"))<br /> {<br /> SqlCommand cmd = new SqlCommand(strSql, conn);<br /> conn.Open();<br /> object orders = cmd.ExecuteScalar();<br /> if (orders == null)<br /> maxOrder = 1;<br /> else<br /> maxOrder = Convert.ToInt32(orders.ToString().TrimStart('0')) + 1;<br /> }<br /> }<br /> else<br /> maxOrder++;</p><p> }</p><p> str.Append(maxOrder.ToString().PadLeft(6,'0'));//6位不足的補0<br /> AddOrders(str.ToString());<br /> Console.WriteLine(str.ToString());<br /> }</p><p> /// <summary><br /> /// 添加訂單記錄<br /> /// </summary><br /> /// <param name="orderno"></param><br /> static void AddOrders(string orderno)<br /> {<br /> string sql = string.Format("insert into OrderTable values('{0}','{1}')", orderno, DateTime.Now.ToString());<br /> SqlConnection conn;<br /> using (conn = new SqlConnection("Data Source=.;Initial Catalog=temp;Integrated Security=True"))<br /> {<br /> try<br /> {<br /> conn.Open();<br /> SqlCommand cmd = new SqlCommand(sql, conn);<br /> cmd.ExecuteNonQuery();<br /> }<br /> catch (Exception ex)<br /> {<br /> Console.WriteLine(ex.Message);<br /> Thread.Sleep(1000);<br /> maxOrder++;<br /> }</p><p> }<br /> }<br /> }