生成唯一的编号

思路:

1.有一个专门的表CONF放最后的编号值,每次从此表中取出值后增减1,如果出错则重复这个过程.

2.取出的值为唯一的值.

public string getbh(string strVkey,string strFlag)
        {
            string strSql,strRet;
            DataRow dr;
            bool lbFlag = false;
            int intLoop = 1;
            int intVal = 0;

            strSql = "select VALUE from CONF where VKEY='" + strVkey + "'";
            dr = this.createRow(strSql);

            strRet = dr[0].ToString();

            do
            {
                try
                {
                    if(strFlag == "+")
                        strRet  = (Convert.ToInt32(strRet)+1).ToString();
                    else
                        strRet  = (Convert.ToInt32(strRet)-1).ToString();

                    strSql = "update CONF set VALUE='" + strRet + "'where VKEY='" + strVkey + "'";
                    lbFlag = this.runSql(strSql);
                    if(lbFlag)
                    {
                        intVal = 1;
                    }
                    else
                    {
                        intVal = 0;
                    }
                }
                catch
                {
                    intVal = 0;
                }
            }while (intVal == 0 && intLoop < 5);

            if (intLoop>=5)
            {
                return "-1";
            }
            else
            {
                return strRet;
            }
        }
}