Delphi ADO连接Oracle字符串

procedure TfrmMain.adoBeforeConnect(Sender: TObject);
var
  s, pwd, userid, servername, dbname, dbPort: string;
begin
  pwd := edtPasswd.Text;
  userid := edtUser.Text;
  servername := edtIp.Text;
  dbname := edtDb.Text;
  dbPort := edtPort.Text;

  s := 'Provider=OraOLEDB.Oracle.1;Password='  
                           +pwd+';Persist Security Info=True;User ID='
                           +userid+';Data Source=(DESCRIPTION = (ADDRESS_LIST =(ADDRESS = (PROTOCOL = TCP)(HOST ='
                           +servername+')(PORT = '+dbPort+')))(CONNECT_DATA =(SERVICE_NAME = '
                           +dbname+')))';
  ado.ConnectionString := s;
end;