django-如果动态URL的pk被更改,则避免错误记录

该应用程序的基本功能是为每个教师生成一个动态的URL,例如:

一切正常,但如果用户(学生)执行一个奇怪的操作,就会出现问题。例如,当学生收费时,老师mike:url生成的是mywebsite.com/teacher/rate/1,并显示一个模板,说明答案已保存。问题出现在这里:

def send(request, user_pk):
    if not request.user.is_authenticated:
        return HttpResponseRedirect('/accounts/login/')
    else:
        #first look for the record not to exist in the DB to avoid duplicate records
        exist = Answers.objects.filter(name= request.user, teacher= user_pk ).exists()
        # if there is not then I proceed to create the record in the database
        if exist == False:
            for key, value in request.POST.items():
                if clave != 'csrfmiddlewaretoken':
                    Answers.objects.create(question=int(clave), answer_to_question=int(valor), student = request.user,teacher = int(user_pk)) 
            #then I change a record in the table of my DB where the finished evaluations are stored, from false to true.  
            actual_state= State.objects.get(student__name = request.user, teacher = user_pk)
            actual_state.finished_evaluation = True
            actual_state.save()
            return render(request,"myapp\send.html") 
        else:
            return render(request,"myapp\error.html")