Question

I have this data access method that return the availability of a lot in our ERP:

public JDEItemLotAvailability GetLotAvailabilityF41021(string _lot)
        {
            JDEItemLotAvailability _retValue = new JDEItemLotAvailability();
            _retValue.Lot = _lot;
            using (OleDbConnection con = new OleDbConnection(_ERPConfig.ConnectionString))
            {
                OleDbCommand cmd = new OleDbCommand();
                cmd.CommandText =
                    "select max(lilotn) lilotn,max(trim(limcu)) limcu,max(lilocn) lilocn," +
                    "max(lipqoh/100) lipqoh,max(liitm) liitm,max(imlitm) imlitm," +
                    "max(concat(imdsc1,imdsc2)) as imdsc,max(imuom1 ) imuom1 " +
                    "from "+ _ERPConfig .AS400Library +".f41021" + " left outer join proddta.f4101 on liitm=imitm " +
                    "where lilotn = ?";
                cmd.Parameters.AddWithValue("@lilotn", _lot);
                cmd.Connection = con;
                con.Open();
                OleDbDataReader rdr = cmd.ExecuteReader();
                if (rdr.HasRows)
                {
                    rdr.Read();
                    if (rdr["lilotn"] != DBNull.Value)
                    {
                        _retValue.Code = rdr.GetString(rdr.GetOrdinal("imlitm"));
                        _retValue.ShortCode = (int)rdr.GetDecimal(rdr.GetOrdinal("liitm"));
                        _retValue.Description = rdr.GetString(rdr.GetOrdinal("imdsc"));
                        _retValue.PrimaryUnitCode = rdr.GetString(rdr.GetOrdinal("imuom1"));
                        _retValue.AvailableQuantity = (int)rdr.GetDecimal(rdr.GetOrdinal("lipqoh"));
                        _retValue.BranchPlant = rdr.GetString(rdr.GetOrdinal("limcu"));
                        _retValue.Location = rdr.GetString(rdr.GetOrdinal("lilocn"));
                    }
                }
            }
            return _retValue;
        }

In case the method doesnt have rows the lot that will be returned has only one data field filled. Thats the way i am checking on above bussiness layer if it was successfull or not.

I dont like it. Someone mentioned tuple as a solution.

I guess i will have my method return a tuple<MyObject, bool> for example ?

Added info: I would like to be able to return also an answer to “why the object is null?”. I am thinking of returning a tuple of object and an ENUM specifying the reason.

UPDATE:

I think i am gonna go this route:

Return a NULL object reference from data access method and have the BLL method return a tuple<Myobject,ENUMreason>

Answer 1

How about just returning null and checking if there is any data in the datalayer so that from any place you use it the behavior will be the same.