go和delphi对数据库查询数据基于结构的遍历

go和delphi对数据库查询数据基于结构的遍历

在结构面前，go的rows，delphi的Tdataset，都是和谐的。特意整理了2篇GO和DELPHI的对比，试图提示跨语言、平台 数据标准的真像。

GO没有Tdataset，但有rows

func UnitsQryPB(w http.ResponseWriter, r *http.Request) {
	// /pb/{service}/units/qry/{dbid}
	url := strings.Split(r.URL.Path, "/")
	dbid := url[5]
	db := getDB(dbid)
	if db == nil {
		return
	}
	sql := "select * from tunit"
	rows, err := db.Query(sql)

	defer rows.Close()
	defer db.Close()

	if err != nil {
		public.Log(err)
		return
	}
	var arr Unitss
	for rows.Next() {
		var dw Units
		rows.Scan(&dw.Unitid, &dw.Unitname)
		arr.UnitsArr = append(arr.UnitsArr, &dw)
	}
	data, _ := proto.Marshal(&arr)
	if public.UseGzip {
		data, _ = public.GZIPEn(data)
	}
	w.Write(data)
}

　　DELPHI没有rows，但有Tdataset

function select(url: string; body: TBytes): TBytes;
var
  db: tdb;
  pool: tdbpool;
  arr: TArray<string>;
  serial: TgoProtocolBuffer;
  rows: TtunitArray;
  i: integer;
  res: TRes;
begin
  serial := TgoProtocolBuffer.Create;
  try
    try
      arr := url.Split(['/']);
      pool := GetDBPool(arr[4]);
      db := pool.Lock;
      db.qry.Close;
      db.qry.SQL.Clear;
      var where: string := '';
      if high(arr) >= 5 then
        where := ' where ' + TNetEncoding.URL.Decode(arr[5]);
      db.qry.SQL.Text := 'select * from tunit' + where;
      db.qry.Open;
      if db.qry.isempty then
      begin
        rows.status := 0;
        rows.exception := 'No found any data.';
        result := serial.Serialize<TtunitArray>(rows);
        exit;
      end;
      SetLength(rows.tunits, db.qry.RecordCount);
      db.qry.First;
      i := 0;
      while not db.qry.Eof do
      begin
        rows.tunits[i].unitid := db.qry.fieldbyname('unitid').asstring;
        rows.tunits[i].unitname := db.qry.fieldbyname('unitname').asstring;
        rows.status := 1;
        rows.message := 'success';
        inc(i);
        db.qry.Next;
      end;
      result := serial.Serialize<TtunitArray>(rows);
    except
      on E: Exception do
      begin
        res.status := 0;
        res.exception := E.message;
        result := serial.Serialize<TRes>(res);
      end;
    end;
  finally
    pool.Unlock(db);
    serial.Free;
  end;
end;