mysql - ruby on Rails 中的随机 id

Question

我根据考试和单独的模块创建了一个测验，我想将其作为每页一个向用户显示，并且还使用此 link_to_remote 随机更改另一个模块

Controller

def answer 
@user = current_user
@student = Student.find_by_admission_no(@user.username)
@exam_group = ExamGroup.find(params[:exam_group_id])
@modules = StudentAdditionalField.find(:all)
@tot_ans = answered.count
@last_ques = (Question.count-1)
@answer = Answer.new 
@ans_id = 1
@ans = Question.find_by_id(random1, :conditions => ['exam_group_id= ? ', @exam_group])
end
def next
@ans_id = 1
@user = current_user
@student = Student.find_by_admission_no(@user.username)
@exam_group = ExamGroup.find_by_id(params[:exam_group_id])
@answer = Answer.new(params[:ans])
@answer.answer = params[:answer]
@answer.exam_group_id = @exam_group.id
@answer.user_id = @user.id
passed_question = params[:passed_question]
@answer.questions_id = passed_question
@question = Question.find_by_id(passed_question)
if params[:answer] == @question.is_answer
  @answer.marks = 1
else
  @answer.marks = 0
end
if @answer.save
  @ans_id = @ans_id + answered.count
  @ans = Question.find_by_id(left_random, :conditions => ['id not in (?) && exam_group_id=?',answered, @exam_group])
  render(:update) do |page|
    page.replace_html 'main', :partial => 'ans', :object => @ans
  end
end
end
def ans
@user = current_user
@student = Student.find_by_admission_no(@user.username)
@exam_group = ExamGroup.find(params[:exam_group_id])
answer = params[:answer]
@tot_ans = answered.count
@last_ques = (Question.count-1)
@answer = answer ? Question.find(is_answer) : nil
if @answer and @answer.correct
  @correct = true
  session[:correct] += 1
else
  @correct = false
end
@total = session[:correct]
render(:update) do |page|
  page.replace_html @ans, :partial => 'ans', :object => @ans
end
end
def final
@user = current_user
@questions = Question.count
@answers = answered.count 
end

def random1
rand_id = rand(Question.count)
if rand_id == 0
  rand_record = Question.first(:offset => rand(rand_id))
else
  rand_record = Question.first(:conditions => [ "id = ?", rand_id])
end
end
private
def answered
@i ||= current_user.answered_questions
end

def left_random
count = Question.count - answered.count
rand = Question.first(:conditions => ['id not in (?)', answered])
end
end

我希望这些问题基于 module_id 按升序排列并且也是随机的数据库表问题是

+----+--------+-----------+-----------------------------+---------------+------+------    +------+------+
| id | ques   | is_answer | student_additional_field_id | exam_group_id | ans1 | ans2 | ans3 | ans4 |
+----+--------+-----------+-----------------------------+---------------+------+------+------+------+
|  1 | df     | ans1      |                           1 |             1 | fd   | d    | df   | daf  |
|  2 | f      | ans2      |                           1 |             1 | dfa  | adf  | af   | adf  |
|  3 | adfdbd | ans4      |                           1 |             1 | zxcv | dvz  | zv   | zcv  |
|  4 | c      | ans4      |                           1 |             1 | aff  | af   | asd  | adf  |
+----+--------+-----------+-----------------------------+---------------+------+------+------+------+ 

其中student_additional_field_id是module_id 请帮帮我 提前致谢

Answer 1

据我所知，您可以使用示例方法:

def left_random
  Question.where('id not in (?)', answered).sample
end

但是问题很棘手，无法得到您需要的东西