Question

我试图在提供的视图（profiles_controller.rb）中显示UserLesson.where（user_id：current_user_id）的数量。目前它显示的是UserLesson总数而不是单个用户。以下是我的观点：

<% @user.lectures.each do |lecture| %>
        <div class="col-md-4 margin-s mb-60">
          <div class="lecture-box">
            <%= image_tag lecture.picture.url(:medium) %>
            <%= lecture.lessons.size %>

            <%= lecture.lessons.total_lesson %> #SHOULD BE HERE

            <p class="pad5"><%= truncate(lecture.description, length: 80) %> </p>
          <%= link_to "Start Now", lecture, class: "btn btn-primary" %>
          </div> <!-- .lecture-box -->
        </div> <!-- .col-md-4 -->
    <% end %>

这是我的课程.rb：

 class Lesson < ActiveRecord::Base
    has_one :lecture, through: :chapter
    belongs_to :chapter 
    has_many :user_lessons

    def self.total_lesson
     Lesson.joins(:user_lessons).size
    end 
 end

其他型号：

 class UserLesson < ActiveRecord::Base
belongs_to :user 
belongs_to :lesson
# validates_uniqueness_of :user_lesson, :scope => [:user, :lesson]
end

 class Lesson < ActiveRecord::Base
   has_one :lecture, through: :chapter
  belongs_to :chapter 
end

     class User < ActiveRecord::Base
   has_many :enrollments
   has_many :user_lessons
   has_many :lectures, through: :enrollments
   accepts_nested_attributes_for :enrollments
 end

class Enrollment < ActiveRecord::Base
belongs_to :user 
belongs_to :lecture
validates :lecture, uniqueness: { scope: :user, message: "should happen once per user" }
 end

class Lecture < ActiveRecord::Base
belongs_to :category
has_many :lessons, through: :chapters, dependent: :destroy 
has_many :chapters
belongs_to :teacher

# For course user relationship 
has_many :enrollments 
has_many :users, through: :enrollments

accepts_nested_attributes_for :enrollments
accepts_nested_attributes_for :chapters

端

 class Chapter < ActiveRecord::Base
    has_many :lessons
    belongs_to :lecture
    accepts_nested_attributes_for :lessons
 end

Answer 1

由于您的视图中有@user（即current_user），因此您只需在视图中调用以下内容即可获得此用户的课程总数：< / p>

Lesson.joins(:user_lessons).where('user_lessons.user_id = ?', @user.id).count

要获得此演讲的课程总数：

Lesson.joins(:user_lessons).joins(:lectures).where('user_lessons.user_id = ? AND lectures.id = ?', @user.id, lecture.id).count

其中lecture是您视图文件中的本地变量。

您应该可以直接在视图中调用此方法以获得所需的计数。

Answer 2

要查找属于与当前用户相关的讲座的课程数量，您可以执行此操作

<%= lecture.lessons.select{ |l| l.users.inculde? current_user }.count %>

但您必须将其添加到Lesson.rb：

has_many :users, through: :user_lessons

ActiveRecord查询用户课程UserLesson

2 个答案: