ActiveRecordを単体で使い1対多の関連を持つ2つのテーブルを作成するサンプルコード

one_to_many_sample.rb

# -*- coding: utf-8 -*-

require 'active_record'

ActiveRecord::Base.establish_connection(
  "adapter" => "sqlite3",
  "database" => "./sample.sqlite")

class CreateWebSite < ActiveRecord::Migration
  def up
    create_table :web_sites do |t|
      t.string :name
      t.string :url
      t.timestamps
    end
  end
end

class CreateBlogArticle < ActiveRecord::Migration
  def up
    create_table :blog_articles do |t|
      t.integer :web_site_id
      t.string  :title
      t.string  :link
      t.timestamps
    end
  end
end

class WebSite < ActiveRecord::Base
  has_many :blog_articles
end

class BlogArticle < ActiveRecord::Base
  belongs_to :web_site
end

CreateWebSite.new.up
CreateBlogArticle.new.up

w = WebSite.new(:name => "tkr's blog", :url => "http://tkr.hatenablog.com/")
a1 = BlogArticle.new(
  :title => "Underscore.jsを再開発する",
  :link  => "http://tkr.hatenablog.com/entry/2013/10/20/200734")
a2 = BlogArticle.new(
  :title => "bundlerの使い方とGemfileの書き方について",
  :link  => "http://tkr.hatenablog.com/entry/2013/09/28/172105")
a3 = BlogArticle.new(
  :title => "ダミーテキストを生成するgemを作った",
  :link  => "http://d.hatena.ne.jp/kasei_san/20120402/p1")

a1.web_site = w; a1.save
a2.web_site = w; a2.save
a3.web_site = w; a3.save
w.save