Help us understand the problem. What is going on with this article?

buildを使って複数のアクティブレコードのオブジェクトを作成する。

More than 3 years have passed since last update.

環境はRails 4.2.2

buildを使って複数のアクティブレコードのオブジェクトを作成する。

テーブルの関係はuserとtagsが1:n。
Modelは下記のような感じで関連付け(アソシエーション)を指定する。

user.rb
class User < ActiveRecord::Base
  has_many :tags
end
tag.rb
class tag < ActiveRecord::Base
  belongs_to :user
end

あとは下記のようにbuildメソッドに配列を渡してやれば、Userに紐付けたTagモデルのActive Record配列が取得できる。

@user = User.first
@tags = @user.tags.build([{ name: "Ruby"}, { name: "Haskell"},{ name: "Lisp"}])
# => [#<Tag id: nil, user_id: 1, name: "Ruby", created_at: nil, updated_at: nil>, #<Tag id: nil, user_id: 1, name: "Haskell", created_at: nil, updated_at: nil>, #<Tag id: nil, user_id: 1, name: "Lisp", created_at: nil, updated_at: nil>]
Why not register and get more from Qiita?
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away
Comments
Sign up for free and join this conversation.
If you already have a Qiita account
Why do not you register as a user and use Qiita more conveniently?
You need to log in to use this function. Qiita can be used more conveniently after logging in.
You seem to be reading articles frequently this month. Qiita can be used more conveniently after logging in.
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away