dephi中如何操作oracle的blob字段

Question

blob里有些文件，想定期备份到磁盘，不知道dephi里是怎么操作blob字段的，请高手指点一二，或者哪里有这方面的字段

Answer 1

用流
//bde
procedure Tfrm_XTDZDDYXX.mn_openpClick(Sender: TObject);var ms:tmemorystream;
begin
opendialog1.Filter:='All (*.'+wjhz0+')|*.'+wjhz0;
if image1.Visible then
  begin
  if opendialog1.Execute then
  begin
    try
    ms:=tmemorystream.Create;
    ms.LoadFromfile(opendialog1.FileName);
    sub_Table.Edit;
    sub_TableNR.LoadFromStream(ms);
    showimage;
    finally
    ms.Free;
    end;
  end;
  end;
end;
//ado
procedure Tfrm_XTDZDDYXX.mn_openpClick(Sender: TObject);
var ms:tmemorystream;
begin
if sub_table.RecordCount<=0 then exit;
//opendialog1.Filter:='All (*.'+wjhz0+')|*.'+wjhz0;
  if opendialog1.Execute then
  begin
    if (getfilesize(opendialog1.FileName)/(1024*1024))>=8.0 then
    begin
      messagebox(handle,pchar('文件大小不能超过8M,请选择其它的文件!'),'错误信息-文件太大',mb_iconerror);
      exit;
    end;
    try
    ms:=tmemorystream.Create;
    ms.LoadFromfile(opendialog1.FileName);
    sub_Table.Edit;
    (sub_Table.FieldByName('nr') as tblobfield).LoadFromStream(ms);
    wjhz0:=uppercase(ExtractFileExt(opendialog1.FileName));
    delete(wjhz0,1,1);
    sub_table.FieldByName('wjhzmc').AsString:=wjhz0;
    sub_Table.post;
    if image1.Visible then
    begin
    showimage;
    end
    else
    begin
    OleContainer1.DestroyObject;
    OleContainer1.CreateObjectFromFile(opendialog1.FileName,false);
    OleContainer1.run;
    OleContainer1.Visible:=true;
    end;
    finally
    ms.Free;
    end;
  end;
end;