如何使用MySQL和Ruby on Rails开发一个简单的在线考试系统

$ ruby -v
$ rails -v
$ mysql -V

$ rails new exam_system

development:
  adapter: mysql2
  encoding: utf8
  database: exam_system_development
  pool: 5
  username: root
  passWord: your_password
  host: localhost

test:
  adapter: mysql2
  encoding: utf8
  database: exam_system_test
  pool: 5
  username: root
  password: your_password
  host: localhost

$ rails db:create

$ rails g model Exam title:string time_limit:integer

$ rails g model Question exam:references content:text answer_a:string answer_b:string answer_c:string answer_d:string correct_answer:integer

$ rails db:migrate

$ rails g controller Exams

class ExamsController < ApplicationController
  def index
    @exams = Exam.all
  end

  def show
    @exam = Exam.find(params[:id])
    @questions = @exam.questions
  end
end

<h1>所有考试</h1>

<table>
  <tr>
    <th>标题</th>
    <th>时间限制</th>
    <th>操作</th>
  </tr>

  <% @exams.each do |exam| %>
    <tr>
      <td><%= exam.title %></td>
      <td><%= exam.time_limit %>分钟</td>
      <td><%= link_to '开始考试', exam %></td>
    </tr>
  <% end %>
</table>

<h1><%= @exam.title %>考试</h1>

<h2>试题列表</h2>

<% @questions.each do |question| %>
  <h3><%= question.content %></h3>
  <ul>
    <li><%= question.answer_a %></li>
    <li><%= question.answer_b %></li>
    <li><%= question.answer_c %></li>
    <li><%= question.answer_d %></li>
  </ul>
<% end %>

$ rails s