ruby-on-rails - 用于测验应用程序的 Rails 关联和数据库设计

Question

我正在构建这个测验应用程序。我希望它有点复杂。

我想出了这个数据库模式。但我真的很困惑..对我需要什么关联和东西感到困惑。

嗯.. 需要注意的一件事是，在创建测试时，没有关于将要参加该测试的候选人数量的信息。所以，我创建了test_questionsandcandidate_answers作为单独的表。

请帮助我与协会。

Answer 1

让我们看看，那将是：

# For Questions: 
:has_many => :answers
:belongs_to => :test_question
  # questions table should have the "test_question_id" column

# Answers:
:has_many => :candidate_answers
:belongs_to => :question 
  # Answers table should have the "question_id" column

#Test Questions:
:has_many => :questions
:has_many => :candidate_answers
:belongs_to => :test
  # test questions table should have the "test_id" column but not the "question_id"

#Tests: 
:has_many => :results
:has_many => :test_questions
:has_many => :candidates, :through => :results, :foreign_key => "candidate_id" #why not? ^^

#Results
:belongs_to => :test
:belongs_to => :candidate
  # Results table should have the "test_id" and "candidate_id" columns

#candidate_answers 
:belongs_to => :candidate
:belongs_to => :test_question
:belongs_to => :answer
  # candidate_answers table should have the "test_question_id", "candidate_id" and "answer_id" columns

#Candidates
:has_many => :candidate_answers
:has_many => :results
:has_many => :answered_tests, :class_name => "test", :through => :results, :foreign_key => "test_id" # again, why not?

根据您提供的信息，这应该可以满足您的需求。;)

Answer 2

这应该这样做：

• 降低candidate_answers.test_question
• 放下candidate_answers桌子

• 放下test_questions桌子

  类测试 < ActiveRecord::Base has_many :results has_many :questions end

  类结果 < ActiveRecord::Base belongs_to :test belongs_to :candidate end

  类候选人 < ActiveRecord::Base has_many :results has_many :answers end

  类答案 < ActiveRecord::Base belongs_to :question belongs_to :candidate end

  类问题 < ActiveRecord::Base belongs_to :test has_many :answers end

看起来您打算将答案重复用于一个以上的问题，这通常是一个坏主意。在这种情况下，最好克隆一个答案。