请大虾指点迷津，我是初学者，看不出错误。
代码如下：
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,adodb, StdCtrls, jpeg, ExtCtrls;

type
  Tlogin = class(TForm)
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  login: Tlogin;
  u_name,u_safe:string;

implementation

{$R *.dfm}

procedure Tlogin.Button1Click(Sender: TObject);
begin
dm.Adslogin.close;
dm.'select * from admin where  uname='+
#39+edit1.text+#39+' and pwd='+ #39+edit2.text+#39;
dm.Adslogin.open;
u_name:=dm.ADSlogin.Fields[0].AsString;
u_safe:=dm.ADSlogin.Fields[2].AsString;
//定义字符串全局变量u_name和u_safe
If dm.adslogin.recordcount=1  then
 begin
 application.MessageBox('欢迎登录本系统!','系统登录',mb_ok+mb_iconinformation+mb_applmodal);
Close;
End
else
Begin
 application.MessageBox('您所输入的用户名或密码错误，请重新输入!','系统登录',mb_ok+mb_iconerror+mb_applmodal);
i:=i+1; //这是一个全局变量，用来统计输入错误的次数。
If i>=3 then
   application.Terminate; //中止程序的运行。
End;


end;

end.

错误如下：
[错误] loginFrm.pas(35): Undeclared identifier: 'dm'
[错误] loginFrm.pas(35): Missing operator or semicolon
[错误] loginFrm.pas(36): Missing operator or semicolon
[错误] loginFrm.pas(38): Missing operator or semicolon
[错误] loginFrm.pas(39): Missing operator or semicolon
[错误] loginFrm.pas(39): Missing operator or semicolon
[错误] loginFrm.pas(40): Missing operator or semicolon
[错误] loginFrm.pas(40): Missing operator or semicolon
[错误] loginFrm.pas(42): 'THEN' expected but identifier 'adslogin' found
[致命错误] Project1.dpr(7): Could not compile used unit 'loginFrm.pas'


[ 本帖最后由 陈俊佳 于 2011-6-15 23:49 编辑 ]