Ruby on rails Rails multiple与同一型号有一个关系

我正在开发一个Rails应用程序，目前我有两个模型-主题和课程。 一门学科有三种不同类型的课程——讲座、辅导课和实验课。我建模，使有3个有一个教训模型

现在，我正在尝试为主题和课程创建嵌套表单，但保存的讲座、教程和实验室始终是第一个呈现的表单。 i、 我有3个嵌套表单，分别用于讲座、教程和实验室，但保存的讲座、教程和实验室始终是第一次构建的表单。在我的代码中，讲座是第一次构建的，因此教程和实验室的属性将遵循我为讲座填写的属性

我不确定我哪里出了问题，或者即使在这种情况下有多个has_-one关系是否有效，因此任何建议都将不胜感激

相关代码如下：

主体模式

class Subject < ActiveRecord::Base

  has_one :lecture, :class_name => "Lesson"
  has_one :laboratory,:class_name => "Lesson"
  has_one :tutorial, :class_name => "Lesson"

  accepts_nested_attributes_for :lecture
  accepts_nested_attributes_for :laboratory
  accepts_nested_attributes_for :tutorial 

end

---

如果有人能帮我找出哪里出了问题，我将不胜感激。如果我不应该创建这样的多个关系，我想就如何实际呈现3个表单以及指示课程类型的默认字段提供一些建议。

我不确定这是否有效，但我的建议是使用AR继承

class Lesson < ActiveRecord::Base
end

class LectureLesson < Lesson
  belongs_to :subject
end

class LaboratyLesson < Lesson
  belongs_to :subject
end

class TutorialLesson < Lesson
  belongs_to :subject
end

class Subject
  has_one :lecture_lesson
  has_one :laboratory_lesson
  has_one :tutorial_lesson

  accepts_nested_attributes_for :lecture_lesson
  accepts_nested_attributes_for :laboratory_lesson
  accepts_nested_attributes_for :tutorial_lesson
end

课程

迁移

class LessonsAndSubjects < ActiveRecord::Migration
  def up
    remove_column :subjects, :lesson_id

    add_column :subjects, :lecture_lesson_id, :integer
    add_column :subjects, :laboratory_lesson_id, :integer
    add_column :subjects, :tutorial_lesson_id, :integer

    add_column :lessons, :type, :string

    add_index :subjects, :lecture_lesson_id
    add_index :subjects, :laboratory_lesson_id
    add_index :subjects, :tutorial_lesson_id
  end

  def down
    remove_column :subjects, :lecture_lesson_id
    remove_column :subjects, :laboratory_lesson_id
    remove_column :subjects, :tutorial_lesson_id

    remove_column :lessons, :type

    add_column :subjects, :lesson_id, :integer
  end
end

class lesson和subjects

---

这更有意义，可能会解决嵌套属性的问题

实际上，从rorra的答案来看，缺少一点，您需要为每个“子项”添加多态关联，以避免出现查询问题

class Lesson < ActiveRecord::Base
  belongs_to :subject
end

class LectureLesson < Lesson
  belongs_to :polymorphic_lecture_lesson, polymorphic: true
end

class Subject
  has_one :lesson
  has_one :lecture_lesson, as: :polymorphic_lecture_lesson

  accepts_nested_attributes_for :lesson
  accepts_nested_attributes_for :lecture_lesson
end

---

非常有用。在我的应用程序中缺少外键声明。

class Lesson < ActiveRecord::Base
end

class LectureLesson < Lesson
  belongs_to :subject
end

class LaboratyLesson < Lesson
  belongs_to :subject
end

class TutorialLesson < Lesson
  belongs_to :subject
end

class Subject
  has_one :lecture_lesson
  has_one :laboratory_lesson
  has_one :tutorial_lesson

  accepts_nested_attributes_for :lecture_lesson
  accepts_nested_attributes_for :laboratory_lesson
  accepts_nested_attributes_for :tutorial_lesson
end

class LessonsAndSubjects < ActiveRecord::Migration
  def up
    remove_column :subjects, :lesson_id

    add_column :subjects, :lecture_lesson_id, :integer
    add_column :subjects, :laboratory_lesson_id, :integer
    add_column :subjects, :tutorial_lesson_id, :integer

    add_column :lessons, :type, :string

    add_index :subjects, :lecture_lesson_id
    add_index :subjects, :laboratory_lesson_id
    add_index :subjects, :tutorial_lesson_id
  end

  def down
    remove_column :subjects, :lecture_lesson_id
    remove_column :subjects, :laboratory_lesson_id
    remove_column :subjects, :tutorial_lesson_id

    remove_column :lessons, :type

    add_column :subjects, :lesson_id, :integer
  end
end

class Lesson < ActiveRecord::Base
  belongs_to :subject
end

class LectureLesson < Lesson
  belongs_to :polymorphic_lecture_lesson, polymorphic: true
end

class Subject
  has_one :lesson
  has_one :lecture_lesson, as: :polymorphic_lecture_lesson

  accepts_nested_attributes_for :lesson
  accepts_nested_attributes_for :lecture_lesson
end

add_column :lessons, :polymorphic_lecture_lesson_id, :integer, index: true
add_column :lessons, :polymorphic_lecture_lesson_type, :integer, index: true