用流保存图片至access解决思路

用流保存图片至access
出错提示Undeclared identifer:'ftBlob' 
不知道怎么解决？
（我知道用流保存）
pjpg:=tjpegimage.Create;
  pjpg.Assign(Image1.Picture.Bitmap);
  pic:=TMemoryStream.Create;
  pjpg.SaveToStream(pic);
  pic.Position:=0;
  TBlobField(ADOQuery.FieldByName('photo')).LoadFromStream(pic);//此处出错，出错提示Undeclared identifer:'ftBlob' 

  pic.Free;
  pjpg.free;




[解决办法]
uses
DB;
[解决办法]
就像下面这样子


unit Unit4;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Buttons, ExtCtrls,DB;