使用Table->Database:='我自定义的数据库'运行时出现Cannot assign to a read-only property,如何解决?

程序如下:
放在onCreate
procedure TForm1.FormCreate(Sender: TObject);
begin
Table1.Database:='horng';
Table1.TableName:='grade.db';
Table1.Open;
btngoto.Enabled:=false;
end;
end.运行时出现
[Error] Unit1.pas(47): Cannot assign to a read-only property
[Fatal Error] Project1.dpr(5): Could not compile used unit 'Unit1.pas'确定是Table1.Database:='horng';出问题!!!
请问如何解决.