在Delphi中从SQLite导出到Excel

Question

我使用TSQLConnection通过以下过程从SqlLite导出数据:

  Campos := TStringList.Create;
  SQLiteConnection.Execute('SELECT * FROM tabela', nil, results);
  if not results.IsEmpty then
  begin
    results.GetFieldNames(Campos);

    XLApp1 := createoleobject('excel.application');
    XLApp1.Workbooks.Add(xlWBatWorkSheet);
    Sheet := XLApp1.Workbooks[1].WorkSheets[1];
    linha := 1;
    begin
       pBar.Max := results.RecordCount;
       for coluna := 0 to results.FieldCount - 1 do
           Sheet.Cells[1, coluna + 1]  :=  Campos[coluna];

       while ( not results.Eof ) do
       begin
          linha := linha + 1;
          for coluna := 0 to results.FieldCount - 1 do
              Sheet.Cells[linha, coluna + 1]  :=  results.FieldByName(campos[coluna]).AsString;
          results.next;
          pBar.Position := pBar.Position + 1;
          Application.ProcessMessages;
       end;
   end;

);

它工作正常.但这需要太多时间才能完成.使用SSD导出带有40,000条记录和45个字段的i7笔记表的35分钟.

所以我的问题是:我有可能做得更快一点吗？

Answer 1

最简单的方法是将所有数据收集到一个变量数组中,然后一次性传递给Excel.很大一部分时间是写入Excel,将其减少到一次写入操作要快得多.

下面的代码改编自代码,以将数据从TStringGrid传输到Excel工作表.Results来自您的原始代码,因此请考虑它的设置与您在上面所指示的完全相同.(下面的代码未经测试修改,因为很明显我没有你的数据可以测试.它与stringgrid一起使用,正如我所提到的 - 我无法测试适应性.如果你遇到问题,请离开评论,我会尝试解决它们.)

使用40个行的35个字段,您可能需要将其分解为块(即使一次执行几百行也会比一次执行一次更大的性能提升).

var
  xls, wb, Range: OLEVariant;
  arrData: Variant;
  RowCount, ColCount, i, j: Integer;
begin
  // Set up your dataset as Result here, just as in your own code
  // ....

  //create variant array where we'll copy our data
  RowCount := Results.RecordCount;
  ColCount := StringGrid1.FieldCount;
  arrData := VarArrayCreate([1, RowCount, 1, ColCount], varVariant);

  //fill array
  j := 1;
  while not Results.Eof do
  begin
    for i := 1 to ColCount do
      arrData[i, j] := Results.Fields[i].AsString;
    Inc(j);
    Results.Next;
  end;

  //initialize an instance of Excel
  xls := CreateOLEObject('Excel.Application');

  //create workbook
  wb := xls.Workbooks.Add;

  //retrieve a range where data must be placed
  Range := wb.WorkSheets[1].Range[wb.WorkSheets[1].Cells[1, 1],
                                  wb.WorkSheets[1].Cells[RowCount, ColCount]];

  //copy data from allocated variant array
  Range.Value := arrData;

  //show Excel with our data
  xls.Visible := True;
end;