procedure Tfrm1.Button2Click(Sender: TObject);
Var
  jpeg: TJPEGImage;
  bmp: TBitmap;
  MyStm:TMemoryStream;
  strfilename,strcard:String;
begin
  inherited;
  strfilename:=extractfilepath(Application.ExeName);
  with DBEdit12.DataSource.DataSet do
  begin
     
        if not  VideoCap1.SaveAsDIB then
        begin
          ShowMessage('拍摄照片失败');
          Abort;
        end;//

        bmp:= TBitmap.Create;
        try
          bmp.LoadFromFile(strfilename+ 'Capture.bmp' );
          MyStm:=TMemoryStream.Create;
          jpeg:= TJPEGImage.Create;
          try
            jpeg.Assign( bmp );
            jpeg.compress;
            jpeg.SaveTofile( strfilename+'Capture.jpg');
            strfilename:=strfilename+'Capture.jpg';
            jpeg.LoadFromFile(strfilename);
            jpeg.SaveToStream(MyStm);
            MyStm.Position:=0;
     OpenQry(query1,'select count(1) as cnt from tb_photo where card_no='''+strcard+'''');//先查找是否有此卡号
     OpenQry(pubqry,'select * from tb_photo where card_no='''+strcard+'''');//打开卡号数据表
     {OpenQry是自定义打开数据表的函数
     OpenQry(qry1:TQuery,ssql:String);
     begin
      with qry1 do
      beign
        if active then
        close;
        sql.clear;
        sql.add(ssql);
        try
         open
        catch
     on E: Exception do ErrorDialog(E.Message, E.HelpContext);
        end;//try
      end;
     end;   
     } 
            with  query1 do
            begin
            if pubqry.Fields[0].AsInteger >0 then  //先判断此卡号的图片是否存在，若存在，替换；否则，插入。
               Edit
            else
               Insert;

               FieldByName('card_no').AsString :=strcard;
               TBlobField(FieldByName('photo')).LoadFromStream(MyStm);
               Post; //统一提交
            end;//with
          finally
            MyStm.Free;
            jpeg.free;
          end;   //try
        finally
          bmp.free;
        end;//try
  end;//with
end;
//请首先下载TVideoCap控件