public String DelSurvey(){
		Long surveyId=Long.valueOf(request.getParameter("sid"));
		SurveyDAO surveydao=DAOFactory.getSurveyDAO(); 
		boolean ret1=surveydao.delSurvey(surveyId);
		QuestionDAO questiondao=DAOFactory.getQuestionDAO();
		
		if(ret1==true)
			ret1=questiondao.delQuestions(surveyId);
	
		if(ret1==true){
			AnswersheetDAO adao=DAOFactory.getAnswersheetDAO();
			ret1=adao.delAnswersheets(surveyId);
		}
		if(ret1==true){
		//	response.sendRedirect("../admin/SurveyAdmin.jsp");
			return "success";
		}else{
			//response.sendRedirect("../admin/OpResult.jsp?op=SurveyDel&ret=false");
			return "fail";
		}
	}