strSql = "SELECT ISNULL(max(substring(User_ID,2,len(User_ID))) + 1,'100') FROM Users";
sqlCmd.CommandText = strSql;
sqlDr = sqlCmd.ExecuteReader();
sqlDr.Read();
UserID = "U" + sqlDr.GetValue(0);
after this i write insert query.
in that insert query my user_Id value will be like this U100,U101... upto U1000. upto this we don't have any problems. after U1000 no one can't insert any record i got error
Violation of PRIMARY KEY constraint 'PK__Users__656C112C'. Cannot insert duplicate key in object 'Users'. The statement has been terminated.
this problem is due to above select query generating User_ID. it can't generate U1001 ... values
could any one please give me any suggessions very urgent