Generating a sequence number

In the development process, often use a sequence number, such as order number, here describes two methods, one is generated Redis, one is Sql

A, Redis SEQ ID generated examples

 public string GetFileName()
        {
            var nextDay = DateTime.Now.AddDays(1);
            var dueTime = new DateTime(nextDay.Year, nextDay.Month, nextDay.Day, 0, 0, 0).Subtract(DateTime.Now);//第二天凌晨过期
            var IncomeNumber = RedisCacheHelper.Instance.GetIncrValue(PictureLibraryConsts.FileNameKey, 1, true, dueTime);
            var fileName = DateTime.Now.ToString("yyyyMMddHHmmss") + IncomeNumber.ToString().PadLeft(8, '0');
            return fileName;
        }

Wherein RedisCacheHelper.Instance.GetIncrValue follows:

 ///  <Summary> 
        /// atomic value retrieved from key according
         ///  </ Summary> 
        ///  <param name = "key"> increment the key </ param> 
        ///  <param name = "key"> value increment of </ param> 
        ///  <param name = "autoRemoveKey"> whether to automatically delete </ param> 
        ///  <param name = "expireTime"> delete key expiration time </ param> 
        ///  <Returns> </ Returns> 
        public  Long GetIncrValue ( String Key, Long value = . 1 , BOOL autoRemoveKey = to true ,TimeSpan expireTime = default(The TimeSpan)) 
        { 
            IF ( String .IsNullOrEmpty (Key)) the throw  new new Exception ( " Key blank " );
             the try 
            { 
                var IncreaseValue = redisClient.Increment (Key, value);
                 // first time acquired, and automatically deleted Key 
                IF (IncreaseValue == . 1 && autoRemoveKey) 
                { 
                    var _expireTime expireTime == = default (the TimeSpan) TimeSpan.FromDays (? 2 ): expireTime; // default time is 2 days 
                     SetExpireTime (key, _expireTime);
                } 
                return increaseValue;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

Second, SQL generated using the sequence number (network from Mu class)

sql paper using the mysql

First, build a table as follows:

New then stored as follows:

CREATE DEFINER=`root`@`localhost` PROCEDURE `CreateOrderNo`()
BEGIN
    DECLARE v_cnt INT;
    DECLARE v_timestr INT;
    DECLARE rowcount BIGINT;
    set v_timestr=DATE_FORMAT(now(),'%Y%m%d');
    select ROUND(rand()*100,0)+1 into v_cnt;
    start TRANSACTION;
        update order_seq set order_sn=order_sn+v_cnt where timestr=v_timestr;
        if row_count()=0 then
            insert into order_seq(timestr,order_sn)VALUES(v_timestr,v_cnt);     
        end if;
        select CONCAT(v_timestr,LPAD(order_sn,7,0)) as order_sn
        from order_seq where timestr=v_timestr;
    COMMIT;
END