怎么更新数据表中的blob字段？

Question

Var
    MS_Question:TMemoryStream;
    MS_Answer:TMemoryStream;
    QuestionID:string;
begin
    QuestionID:=Label_QuestionID.Caption;
    MS_Question:=TMemoryStream.Create;
    MS_Answer:=TMemoryStream.Create;
    OLE_Question.SaveToStream(MS_Question);
    OLE_Answer.SaveToStream(MS_Answer);
End;
我要将数据表中id为QuestionID的MS_Question、MS_Answer进行更新，不知道怎么做？

Answer 1

先定位
  Query1.Close;
  Query1.Sql.text := 'select * from table where id = '''+QuestionID+'''';
  Query1.Open;修改
  TBlobField(Query1.FieldByName('MS_Question')).LoadFromStream(MS_Question);
  TBlobField(Query1.FieldByName('MS_Answer')).LoadFromStream(MS_Answer);

Answer 2

The following example copies the data in the Notes field of Table1 or SQLDataSet1 to the Res field of ClientDataSet1.
procedure TForm1.Button1Click(Sender: TObject);
var
  Stream1: TBlobStream;
  Stream2: TStream;
begin
  Stream1 := TBlobStream.Create(Table1Notes, bmRead);
  try
    ClientDataSet1.Edit;
    { here抯 a different way to create a blob stream } 
    Stream2 := ClientDataSet1.CreateBlobStream(ClientDataSet1.FieldByName('Res'), bmReadWrite);
    try
      Stream2.CopyFrom(Stream1, Stream1.Size);
      ClientDataSet1.Post;
    finally
      Stream2.Free;
    end;  finally
    Stream1.Free;
  end;
end;