Question

我有两个模型，Collection和Book。一本书属于一个集合，一个集合有很多书。

我以这种方式生成了我的模型：

bin/rails generate model Collection title:string plot:text
bin/rails generate model Book title:string plot:text Collection:references

然后它生成这些模型：

class Book < ActiveRecord::Base
  belongs_to :Collection
end

class Collection < ActiveRecord::Base
end

所以我已经读过像这样的其他答案has_many, belongs_to relation in active record migration rails 4我必须在Collection模型中手动添加has_many字段。

好的，它看起来像这样：

class Collection < ActiveRecord::Base
  has_many :books
end

然后我运行迁移：

bin/rake db:migrate

然后我添加一些数据，几本书和一个集合（我不确定收集帖是否正确）：

curl -H 'Content-Type: application/json' -X POST -d '{"title" : "Book 1", "plot" : "book"}' http://127.0.0.1:3000/books
curl -H 'Content-Type: application/json' -X POST -d '{"title" : "Book 2", "plot" : "book"}' http://127.0.0.1:3000/books
curl -H 'Content-Type: application/json' -X POST -d '{"title" : "Collection", "plot" : "collection", "book_id" : [1,2]}' http://127.0.0.1:3000/collections

然后我在http://127.0.0.1:3000/collections检查它们并崩溃

  def index
    @collections = Collection.all
    render :json => @collections.as_json(
                  :include => :book
                )
  end

它说

#p>未定义的方法`book'for＃Did you 意思？书籍书籍

如果我尝试并用书替换书籍，那么书籍清单是空的：

[{"id":1,"title":"Collection","plot":"collection","created_at":"2016-04-11T17:53:38.892Z","updated_at":"2016-04-11T17:53:38.892Z","books":[]}]

这是我的创建方法：

  def create
    @collection = Collection.new(collection_params)

    @collection.save
    redirect_to @collection
  end

  private
    def collection_params
      params.permit(:title, :plot, :book_id)
    end

它不应该把书存放在收藏中吗？为什么不出现在索引视图中？

Answer 1

如果书籍属于馆藏，那么你希望collection_id能够存在于书籍表中，然后在创建数据时你想要这样做：

curl -H 'Content-Type: application/json' -X POST -d '{
  "title" : "Collection", 
  "plot" : "collection"}' 
http://127.0.0.1:3000/collections

curl -H 'Content-Type: application/json' -X POST -d '{
  "title" : "Book 1", 
  "plot" : "book", 
  "collection_id": "1"}' 
http://127.0.0.1:3000/books

curl -H 'Content-Type: application/json' -X POST -d '{
  "title" : "Book 2", 
  "plot" : "book", 
  "collection_id": "1"}' 
http://127.0.0.1:3000/books

Rails生成has_many迁移

1 个答案: