Question

使用Ruby on Rails，我认为我需要创建一个自引用的has_many关联来模拟中文单词。

背景：

每个单词都是多个组件单词的复合。

例如，如果我有三个单词，＆＃39; ni＆＃39;，＆＃39; hao＆＃39;和＆＃39; nihao＆＃39;，我希望能够这样做：

nihao.components = ['ni', 'hao']
和
'ni'.composites = ['nihao']
'hao'.composites =['nihao']

我不相信这应该是一个等级关联（我已经看过几个宝石......），因为一个词没有1或2＆＃34;父母＆＃34;，它有0,1或数百个＆＃34;复合材料＆＃34;。同样，一个单词有0,1或几个＆＃34;组件＆＃34;。

我试过了：

class Word < ActiveRecord::Base
  has_many :relationships
  has_many :components, through: :relationships, foreign_key: :component_id
  has_many :composites, through: :relationships, foreign_key: :composite_id
end

class Relationship < ActiveRecord::Base
  belongs_to :component, class_name: "Word"
  belongs_to :composite, class_name: "Word"
end

这不完全正确，因为我无法添加组件：

nihao.components << ni
   (0.2ms)  BEGIN
   (0.2ms)  ROLLBACK
ActiveModel::UnknownAttributeError: unknown attribute 'word_id' for Relationship.
        from (irb):5

数据库架构：

create_table "relationships", force: :cascade do |t|
    t.integer "component_id"
    t.integer "composite_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "words", force: :cascade do |t|
    t.string "characters"
    t.string "pinyin"
    t.string "opinyin"
    t.string "tpinyin"
    t.string "english"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

Answer 1

试试这个，你没有正确地将你的模型与这种用例联系起来。

class Word < ActiveRecord::Base
  has_many :component_relationships, class_name: 'Relationship', foreign_key: :composite_id
  has_many :composite_relationships, class_name: 'Relationship', foreign_key: :component_id

  has_many :components, through: :component_relationships
  has_many :composites, through: :composite_relationships
end 

class Relationship < ActiveRecord::Base
  belongs_to :component, class_name: "Word", foreign_key: :component_id
  belongs_to :composite, class_name: "Word", foreign_key: :composite_id
end

我没试过这个，但这应该有效。

Rails自我引用has_many关联

1 个答案: