Rails 5.2：活动管理员Has_One关系错误

Question

我当然有模型，每个课程有很多单元，每个单元有很多视频，都有一个测验，最后每个测验都有很多问题。

当我尝试添加新课程或编辑一门课程时，这是我得到的错误：

  

＃的未定义方法“ has_one”   你的意思是？ has_many

这是我的模特

Course.rb

class Course < ApplicationRecord
  validates_presence_of :title
  validates_presence_of :author

  has_many :units, dependent: :destroy, autosave: true
  accepts_nested_attributes_for :units, allow_destroy: true
  acts_as_paranoid
end

Unit.rb

class Unit < ApplicationRecord
  validates_presence_of :name
  validates_presence_of :course_id
  belongs_to :course

  has_many :videos, dependent: :destroy, autosave: true
  has_one :quiz, dependent: :destroy, autosave: true

  accepts_nested_attributes_for :videos, allow_destroy: true
  accepts_nested_attributes_for :quiz, allow_destroy: true

  acts_as_paranoid
end

Video.rb

class Video < ApplicationRecord
  validates :data ,presence: true
  validates_presence_of :unit
  validates_presence_of :unit_id
  validates_presence_of :name

  belongs_to :unit
  acts_as_paranoid
end

Quiz.rb

class Quiz < ApplicationRecord
  validates_presence_of :name
  validates_presence_of :unit
  validates_presence_of :unit_id

  belongs_to :unit
  has_many :questions, :dependent => :destroy, :autosave => true

  accepts_nested_attributes_for :questions, allow_destroy: true
  acts_as_paranoid

end

Question.rb

class Question < ApplicationRecord
  validates :question ,presence: true
  validates :answer1 ,presence: true
  validates :answer2 ,presence: true
  validates :answer3 ,presence: true
  validates :answer4 ,presence: true
  validates :correct ,presence: true
  validates_presence_of :segment

  belongs_to :quiz

  acts_as_paranoid
end

这是活动管理员中的courses.rb：

ActiveAdmin.register Course do
  permit_params :id, :title, :author, :course_details, :course_expectations, :course_time, :course_topics, :course_additional_resources,
                units_attributes: [:id, :name, :_destroy, :_create, :_update,
                  videos_attributes: [:id, :name, :data],
                  quiz_attributes: [:id, :name,
                    questions_attributes: [:id, :question, :answer1, :answer2, :answer3, :answer4, :correct, :_destroy, :_create, :_update]]]

  config.sort_order = 'id_asc'
  active_admin_paranoia


  # /admin/course/:id/units
  member_action :units do
    @units = resource.units
    # This will render app/views/admin/courses/units.html.erb
  end

  index do
    column :id
    column :title
    column :author
    actions
  end

  show do
    panel "About this course" do
      div do
        label "Course Topics:"
        span course.course_topics
      end
      div do
        label "Course Expectations:"
        span course.course_expectations
      end
      div do
        label "Time:"
        span course.course_time
      end
      div do
        label "Additional Resources:"
        span course.course_additional_resources
      end
    end

    panel "Course Overview" do
      table_for course.units do
        column "Unit name", :name
        column(:videos) {|unit|
          table_for unit.videos do
            column :id
            column :name
            column :data
          end
        }
        column(:quiz) { |unit|
          if unit.quiz
            table_for unit.quiz do
              column :id
              column :name
              column :question
              column :answer1
              column :answer2
              column :answer3
              column :answer4
              column :correct
            end
          else
            'No Quiz'
          end
        }
      end
    end

    active_admin_comments
  end

  sidebar "Course Units", only: :show do
  # sidebar "Course Details", only: :show do
    # attributes_table_for course do
    #   row :title
    #   row :author
    # end
    table_for Unit.joins(:course).where(:course_id => course.id) do |t|
      t.column("Title") { |unit| unit.name }
    end
  end

form do |f|
  tabs do
    tab 'Basic Info' do
      f.inputs "Course details" do
        f.input :title
        f.input :author
        f.input :course_topics
        f.input :course_expectations
        f.input :course_time
        f.input :course_additional_resources
      end
    end

    tab 'Content' do
      f.inputs "Units" do
        f.has_many :units, heading: false, allow_destroy: true do |unit|
          unit.input :name
          unit.has_many :videos, heading: false, allow_destroy: true do |video|
              video.input :name
              video.input :data, label: 'Url', :as => :string, input_html: { class: 'video-tab' }
          end

          unit.has_one :quiz, heading: false, allow_destroy: true do |quiz|
            quiz.has_many :questions, heading: false, allow_destroy: true do |q|
              q.input :question, input_html: { class: 'quiz-tab' }
              q.input :answer1, input_html: { class: 'quiz-tab' }
              q.input :answer2, input_html: { class: 'quiz-tab' }
              q.input :answer3, input_html: { class: 'quiz-tab' }
              q.input :answer4, input_html: { class: 'quiz-tab' }
              q.input :correct, input_html: { class: 'quiz-tab' }, as: :select, collection: [1,2,3,4]
            end
          end
        end
      end
    end
  end
    f.actions
end

end