public List <PreValue> GetAllPreValues(Field field)
        {
            List <PreValue> l   = new List <PreValue>();
            string          sql = "SELECT * From UFprevalues where field = @field";

            IRecordsReader rr = sqlHelper.ExecuteReader(sql,
                                                        sqlHelper.CreateParameter("@field", field.Id));

            while (rr.Read())
            {
                PreValue pv = PreValue.CreateFromDataReader(rr);
                l.Add(pv);
            }

            rr.Dispose();
            return(l);
        }
        public PreValue GetPreValue(Guid id)
        {
            string sql = "SELECT * From UFprevalues where id = @id";

            IRecordsReader rr = sqlHelper.ExecuteReader(sql,
                                                        sqlHelper.CreateParameter("@id", id));

            PreValue pv = new PreValue();

            if (rr.Read())
            {
                pv = PreValue.CreateFromDataReader(rr);

                return(pv);
            }
            rr.Dispose();
            return(pv);
        }