ActiveRecord\u306f\u3001Ruby on Rails\u306e\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u3092\u62c5\u3046\u91cd\u8981\u306a\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3067\u3059\u3002\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u6307\u5411\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3068\u30ea\u30ec\u30fc\u30b7\u30e7\u30ca\u30eb\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u6a4b\u6e21\u3057\u3092\u884c\u3046OR\u30de\u30c3\u30d1\u30fc\uff08Object-Relational Mapper\uff09\u3068\u3057\u3066\u6a5f\u80fd\u3057\u3001\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u3092\u76f4\u611f\u7684\u306b\u884c\u3046\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u76ee\u6b21 <\/p>\n
# \u5f93\u6765\u306eSQL\n# SELECT * FROM users WHERE age >= 20 ORDER BY created_at DESC LIMIT 10;\n\n# ActiveRecord\u3092\u4f7f\u7528\u3057\u305f\u5834\u5408\nUser.where('age >= ?', 20).order(created_at: :desc).limit(10)<\/pre>\n\n\n\n\n- \u30e2\u30c7\u30eb\u3068\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u4e00\u5143\u7ba1\u7406<\/strong><\/li>\n<\/ol>\n\n\n\n
\n- \u30c6\u30fc\u30d6\u30eb\u30b9\u30ad\u30fc\u30de\u306e\u5909\u66f4\u3092\u30de\u30a4\u30b0\u30ec\u30fc\u30b7\u30e7\u30f3\u30d5\u30a1\u30a4\u30eb\u3067\u7ba1\u7406<\/li>\n\n\n\n
- \u30e2\u30c7\u30eb\u306e\u95a2\u9023\u4ed8\u3051\u3092\u76f4\u611f\u7684\u306b\u5b9a\u7fa9\u53ef\u80fd<\/li>\n<\/ul>\n\n\n\n
class User < ApplicationRecord\n # has_many\u306b\u3088\u308b1\u5bfe\u591a\u306e\u95a2\u9023\u4ed8\u3051\n has_many :posts\n\n # \u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306e\u5b9a\u7fa9\n validates :email, presence: true, uniqueness: true\n validates :age, numericality: { greater_than_or_equal_to: 0 }\nend<\/pre>\n\n\n\n\n- \u30c7\u30fc\u30bf\u306e\u6574\u5408\u6027\u7dad\u6301\u306e\u81ea\u52d5\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n
\n- \u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306b\u3088\u308b\u30c7\u30fc\u30bf\u691c\u8a3c\u306e\u81ea\u52d5\u5316<\/li>\n\n\n\n
- \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406\u306e\u7c21\u7565\u5316<\/li>\n\n\n\n
- \u95a2\u9023\u3059\u308b\u30ec\u30b3\u30fc\u30c9\u306e\u6574\u5408\u6027\u7ba1\u7406<\/li>\n<\/ul>\n\n\n\n
ActiveRecord\u306e\u52d5\u4f5c\u306e\u4ed5\u7d44\u307f\u3068\u91cd\u8981\u306a\u6982\u5ff5<\/h2>\n\n\n\n1. \u30e2\u30c7\u30eb\u306e\u7d99\u627f\u3068\u30b9\u30ad\u30fc\u30de\u306e\u81ea\u52d5\u8a8d\u8b58<\/h3>\n\n\n\n
ActiveRecord\u306fApplicationRecord<\/code>\uff08\u307e\u305f\u306fActiveRecord::Base<\/code>\uff09\u3092\u7d99\u627f\u3059\u308b\u3053\u3068\u3067\u3001\u5bfe\u5fdc\u3059\u308b\u30c6\u30fc\u30d6\u30eb\u306e\u30b9\u30ad\u30fc\u30de\u3092\u81ea\u52d5\u7684\u306b\u8a8d\u8b58\u3057\u307e\u3059\u3002<\/p>\n\n\n\n# app\/models\/product.rb\nclass Product < ApplicationRecord\n # \u30c6\u30fc\u30d6\u30eb\u540d\u306f\u81ea\u52d5\u7684\u306b'products'\u3068\u8a8d\u8b58\u3055\u308c\u308b\n # \u30ab\u30e9\u30e0\u60c5\u5831\u3082\u81ea\u52d5\u7684\u306b\u53d6\u5f97\u3055\u308c\u308b\nend\n\n# \u30e2\u30c7\u30eb\u306e\u4f7f\u7528\u4f8b\nproduct = Product.new(\n name: \"Ruby\u672c\",\n price: 3000\n)\nproduct.save # INSERT\u6587\u304c\u81ea\u52d5\u751f\u6210\u3055\u308c\u308b<\/pre>\n\n\n\n2. \u547d\u540d\u898f\u5247\uff08Convention over Configuration\uff09<\/h3>\n\n\n\n
ActiveRecord\u306f\u4ee5\u4e0b\u306e\u547d\u540d\u898f\u5247\u306b\u5f93\u3044\u307e\u3059\uff1a<\/p>\n\n\n
\n\u30e2\u30c7\u30eb\uff08\u5358\u6570\u5f62\uff09<\/th> \u30c6\u30fc\u30d6\u30eb\uff08\u8907\u6570\u5f62\uff09<\/th> \u5916\u90e8\u30ad\u30fc<\/th><\/tr><\/thead> User<\/td> users<\/td> user_id<\/td><\/tr> Category<\/td> categories<\/td> category_id<\/td><\/tr> Person<\/td> people<\/td> person_id<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n3. \u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u3068\u30aa\u30d6\u30b6\u30fc\u30d0\u30fc<\/h3>\n\n\n\n
\u30e2\u30c7\u30eb\u306e\u4fdd\u5b58\u3084\u66f4\u65b0\u6642\u306b\u81ea\u52d5\u7684\u306b\u51e6\u7406\u3092\u5b9f\u884c\u3067\u304d\u307e\u3059\uff1a<\/p>\n\n\n\n
class User < ApplicationRecord\n # \u4fdd\u5b58\u524d\u306b\u5b9f\u884c\n before_save :ensure_name_has_a_value\n\n # \u4f5c\u6210\u5f8c\u306b\u5b9f\u884c\n after_create :send_welcome_email\n\n private\n\n def ensure_name_has_a_value\n self.name = 'Anonymous' if name.blank?\n end\n\n def send_welcome_email\n UserMailer.welcome(self).deliver_later\n end\nend<\/pre>\n\n\n\n4. Dirty Object Tracking<\/h3>\n\n\n\n
\u30e2\u30c7\u30eb\u306e\u5c5e\u6027\u5909\u66f4\u3092\u8ffd\u8de1\u3059\u308b\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n
user = User.find(1)\nuser.name = \"\u65b0\u3057\u3044\u540d\u524d\"\n\nuser.changed? # => true\nuser.changes # => {\"name\"=>[\"\u53e4\u3044\u540d\u524d\", \"\u65b0\u3057\u3044\u540d\u524d\"]}\nuser.name_changed? # => true\nuser.name_was # => \"\u53e4\u3044\u540d\u524d\"<\/pre>\n\n\n\n\u3053\u306e\u3088\u3046\u306b\u3001ActiveRecord\u306f\u8c4a\u5bcc\u306a\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u306a\u304c\u3089\u3001\u76f4\u611f\u7684\u306aAPI\u3067\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u3092\u53ef\u80fd\u306b\u3057\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u57fa\u672c\u77e5\u8b58\u3092\u6d3b\u7528\u3057\u305f\u5b9f\u8df5\u7684\u306a\u30c6\u30af\u30cb\u30c3\u30af\u3092\u7d39\u4ecb\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
ActiveRecord\u3092\u4f7f\u3044\u3053\u306a\u3059\u305f\u3081\u306e\u5b9f\u8df5\u30c6\u30af\u30cb\u30c3\u30af<\/h1>\n\n\n\n\u8907\u96d1\u306a\u95a2\u9023\u4ed8\u3051\u3092\u52b9\u7387\u7684\u306b\u6271\u3046\u65b9\u6cd5<\/h2>\n\n\n\n1. \u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u95a2\u9023\u4ed8\u3051\u306e\u5b9f\u88c5<\/h3>\n\n\n\n
\u8907\u6570\u306e\u30e2\u30c7\u30eb\u306b\u5bfe\u3057\u3066\u540c\u3058\u95a2\u9023\u4ed8\u3051\u3092\u8a2d\u5b9a\u3059\u308b\u5834\u5408\u306b\u6709\u52b9\u3067\u3059\uff1a<\/p>\n\n\n\n
# app\/models\/comment.rb\nclass Comment < ApplicationRecord\n belongs_to :commentable, polymorphic: true\nend\n\n# app\/models\/post.rb\nclass Post < ApplicationRecord\n has_many :comments, as: :commentable\nend\n\n# app\/models\/photo.rb\nclass Photo < ApplicationRecord\n has_many :comments, as: :commentable\nend\n\n# \u4f7f\u7528\u4f8b\npost = Post.first\npost.comments.create(content: \"Great post!\")\n\nphoto = Photo.first\nphoto.comments.create(content: \"Nice photo!\")<\/pre>\n\n\n\n2. \u5165\u308c\u5b50\u95a2\u4fc2\u306e\u52b9\u7387\u7684\u306a\u51e6\u7406<\/h3>\n\n\n\n
accepts_nested_attributes_for\u3092\u4f7f\u7528\u3057\u3066\u3001\u89aa\u5b50\u95a2\u4fc2\u306e\u3042\u308b\u8907\u6570\u306e\u30e2\u30c7\u30eb\u3092\u4e00\u5ea6\u306b\u66f4\u65b0\u3067\u304d\u307e\u3059\uff1a<\/p>\n\n\n\n
class Order < ApplicationRecord\n has_many :order_items\n accepts_nested_attributes_for :order_items, allow_destroy: true\n\n # \u7279\u5b9a\u306e\u6761\u4ef6\u3067\u5b50\u30ec\u30b3\u30fc\u30c9\u3092\u524a\u9664\n accepts_nested_attributes_for :order_items,\n reject_if: proc { |attributes| attributes['quantity'].blank? }\nend\n\n# \u30d5\u30a9\u30fc\u30e0\u304b\u3089\u306e\u9001\u4fe1\u30c7\u30fc\u30bf\u3092\u4e00\u62ec\u3067\u4fdd\u5b58\nOrder.create(\n customer: \"\u5c71\u7530\u592a\u90ce\",\n order_items_attributes: [\n { product_id: 1, quantity: 2 },\n { product_id: 2, quantity: 1 }\n ]\n)<\/pre>\n\n\n\n\u30d0\u30eb\u30af\u30a4\u30f3\u30b5\u30fc\u30c8\u30fb\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u306e\u5b9f\u88c5\u65b9\u6cd5<\/h2>\n\n\n\n1. insert_all\u306b\u3088\u308b\u4e00\u62ec\u633f\u5165<\/h3>\n\n\n\n# \u8907\u6570\u30ec\u30b3\u30fc\u30c9\u3092\u4e00\u5ea6\u306b\u633f\u5165\nUser.insert_all([\n { name: '\u5c71\u7530', email: 'yamada@example.com' },\n { name: '\u7530\u4e2d', email: 'tanaka@example.com' }\n], returning: %w[ id name ])\n\n# \u30bf\u30a4\u30e0\u30b9\u30bf\u30f3\u30d7\u3092\u81ea\u52d5\u8a2d\u5b9a\nUser.insert_all(\n [ { name: '\u4f50\u85e4' }, { name: '\u9234\u6728' } ],\n record_timestamps: true\n)<\/pre>\n\n\n\n2. update_all\u306b\u3088\u308b\u4e00\u62ec\u66f4\u65b0<\/h3>\n\n\n\n# \u6761\u4ef6\u306b\u5408\u81f4\u3059\u308b\u5168\u30ec\u30b3\u30fc\u30c9\u3092\u66f4\u65b0\nUser.where(active: true)\n .update_all(newsletter: true)\n\n# \u8907\u6570\u306e\u30ab\u30e9\u30e0\u3092\u540c\u6642\u306b\u66f4\u65b0\nProduct.where('price > ?', 1000)\n .update_all('price = price * 0.9, updated_at = ?', Time.current)<\/pre>\n\n\n\n\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406\u306e\u6b63\u3057\u3044\u4f7f\u3044\u65b9<\/h2>\n\n\n\n1. \u57fa\u672c\u7684\u306a\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h3>\n\n\n\nActiveRecord::Base.transaction do\n david.withdraw(100)\n mary.deposit(100)\nend<\/pre>\n\n\n\n2. \u30cd\u30b9\u30c8\u3057\u305f\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h3>\n\n\n\nUser.transaction do\n User.create!(name: '\u5c71\u7530')\n\n # \u30cd\u30b9\u30c8\u3057\u305f\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\n Account.transaction(requires_new: true) do\n Account.create!(user_id: user.id, balance: 0)\n rescue StandardError\n # \u3053\u306e\u4f8b\u5916\u306f\u30cd\u30b9\u30c8\u3057\u305f\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u307f\u3092\u30ed\u30fc\u30eb\u30d0\u30c3\u30af\n raise ActiveRecord::Rollback\n end\n\n # \u5916\u5074\u306e\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306f\u7d99\u7d9a\nend<\/pre>\n\n\n\n3. \u6761\u4ef6\u4ed8\u304d\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h3>\n\n\n\ndef transfer_money(from_account, to_account, amount)\n Account.transaction(isolation: :serializable) do\n # \u6b8b\u9ad8\u30c1\u30a7\u30c3\u30af\n raise InsufficientBalanceError unless from_account.sufficient_balance?(amount)\n\n from_account.withdraw(amount)\n to_account.deposit(amount)\n\n # \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u5b8c\u4e86\u3092\u4fdd\u8a3c\n raise ActiveRecord::Rollback unless from_account.save && to_account.save\n end\nrescue ActiveRecord::RecordInvalid\n # \u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u30a8\u30e9\u30fc\u306e\u51e6\u7406\n false\nend<\/pre>\n\n\n\n\u91cd\u8981\u306a\u5b9f\u88c5\u306e\u30dd\u30a4\u30f3\u30c8<\/h3>\n\n\n\n\n- \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u5206\u96e2\u30ec\u30d9\u30eb<\/strong><\/li>\n<\/ol>\n\n\n\n
\n:read_uncommitted<\/code><\/li>\n\n\n\n:read_committed<\/code><\/li>\n\n\n\n:repeatable_read<\/code><\/li>\n\n\n\n:serializable<\/code><\/li>\n<\/ul>\n\n\n\n# \u5206\u96e2\u30ec\u30d9\u30eb\u306e\u6307\u5b9a\nPost.transaction(isolation: :serializable) do\n # \u53b3\u5bc6\u306a\u76f4\u5217\u5316\u304c\u5fc5\u8981\u306a\u51e6\u7406\nend<\/pre>\n\n\n\n\n- \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u5bfe\u7b56<\/strong><\/li>\n<\/ol>\n\n\n\n
retry_count = 0\nbegin\n Post.transaction do\n # \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u306e\u53ef\u80fd\u6027\u304c\u3042\u308b\u51e6\u7406\n end\nrescue ActiveRecord::Deadlocked\n retry_count += 1\n raise if retry_count > 3\n sleep(0.1 * retry_count)\n retry\nend<\/pre>\n\n\n\n\n- \u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u3068\u306e\u9023\u643a<\/strong><\/li>\n<\/ol>\n\n\n\n
class Order < ApplicationRecord\n after_commit :send_confirmation_email, on: :create\n after_rollback :notify_admin_of_failure\n\n private\n\n def send_confirmation_email\n OrderMailer.confirmation(self).deliver_later\n end\n\n def notify_admin_of_failure\n AdminNotifier.failure_alert(self).deliver_now\n end\nend<\/pre>\n\n\n\n\u3053\u308c\u3089\u306e\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u64cd\u4f5c\u3092\u3055\u3089\u306b\u6700\u9069\u5316\u3059\u308b\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\u3059\u308bActiveRecord\u306e\u4f7f\u3044\u65b9<\/h1>\n\n\n\nN+1\u554f\u984c\u3092\u56de\u907f\u3059\u308bincludes\u306e\u52b9\u679c\u7684\u306a\u4f7f\u7528\u6cd5<\/h2>\n\n\n\nN+1\u554f\u984c\u3068\u306f<\/h3>\n\n\n\n
N+1\u554f\u984c\u306f\u3001\u95a2\u9023\u4ed8\u3051\u3089\u308c\u305f\u30ec\u30b3\u30fc\u30c9\u3092\u53d6\u5f97\u3059\u308b\u969b\u306b\u767a\u751f\u3059\u308b\u4f59\u5206\u306a\u30af\u30a8\u30ea\u767a\u884c\u306e\u554f\u984c\u3067\u3059\u3002\u4ee5\u4e0b\u306e\u4f8b\u3067\u8aac\u660e\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n
# N+1\u554f\u984c\u304c\u767a\u751f\u3059\u308b\u30b3\u30fc\u30c9\nposts = Post.all\nposts.each do |post|\n puts post.user.name # \u5404\u6295\u7a3f\u306b\u5bfe\u3057\u3066\u30e6\u30fc\u30b6\u30fc\u60c5\u5831\u3092\u53d6\u5f97\u3059\u308b\u30af\u30a8\u30ea\u304c\u767a\u884c\u3055\u308c\u308b\nend\n\n# \u5b9f\u884c\u3055\u308c\u308bSQL\n# SELECT * FROM posts\n# SELECT * FROM users WHERE id = 1\n# SELECT * FROM users WHERE id = 2\n# SELECT * FROM users WHERE id = 3\n# ...<\/pre>\n\n\n\nincludes\/preload\u306b\u3088\u308b\u89e3\u6c7a<\/h3>\n\n\n\n# N+1\u554f\u984c\u3092\u89e3\u6c7a\u3059\u308b\u30b3\u30fc\u30c9\nposts = Post.includes(:user)\nposts.each do |post|\n puts post.user.name # \u8ffd\u52a0\u306e\u30af\u30a8\u30ea\u306f\u767a\u884c\u3055\u308c\u306a\u3044\nend\n\n# \u5b9f\u884c\u3055\u308c\u308bSQL\n# SELECT * FROM posts\n# SELECT * FROM users WHERE id IN (1, 2, 3, ...)<\/pre>\n\n\n\n\u8907\u96d1\u306a\u95a2\u9023\u4ed8\u3051\u3067\u306e\u6700\u9069\u5316<\/h3>\n\n\n\n# \u8907\u6570\u306e\u95a2\u9023\u4ed8\u3051\u3092\u540c\u6642\u306b\u6700\u9069\u5316\nposts = Post.includes(:user, comments: :user)\n\n# \u6761\u4ef6\u4ed8\u304d\u306e\u95a2\u9023\u4ed8\u3051\nposts = Post.includes(:comments)\n .where(comments: { status: 'approved' })\n .references(:comments)\n\n# \u30cd\u30b9\u30c8\u3057\u305f\u95a2\u9023\u4ed8\u3051\nposts = Post.includes(comments: [{ user: :profile }, :likes])<\/pre>\n\n\n\n\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\u3057\u305f\u30af\u30a8\u30ea\u306e\u9ad8\u901f\u5316\u624b\u6cd5<\/h2>\n\n\n\n1. \u9069\u5207\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u8a2d\u8a08<\/h3>\n\n\n\n# \u30de\u30a4\u30b0\u30ec\u30fc\u30b7\u30e7\u30f3\u3067\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u8a2d\u5b9a\nclass AddIndexesToPosts < ActiveRecord::Migration[7.0]\n def change\n # \u5358\u4e00\u30ab\u30e9\u30e0\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n add_index :posts, :published_at\n\n # \u8907\u5408\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n add_index :posts, [:user_id, :published_at]\n\n # \u30e6\u30cb\u30fc\u30af\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n add_index :posts, :slug, unique: true\n\n # \u90e8\u5206\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n add_index :posts, :published_at, \n where: \"status = 'published'\"\n end\nend<\/pre>\n\n\n\n2. \u30af\u30a8\u30ea\u6700\u9069\u5316\u306e\u5b9f\u8df5\u4f8b<\/h3>\n\n\n\n# \u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\u3059\u308b\u30af\u30a8\u30ea\nclass Post < ApplicationRecord\n # \u983b\u7e41\u306b\u4f7f\u7528\u3055\u308c\u308b\u691c\u7d22\u6761\u4ef6\u306b\u30b9\u30b3\u30fc\u30d7\u3092\u5b9a\u7fa9\n scope :recent_published, -> {\n where(status: 'published')\n .order(published_at: :desc)\n .limit(10)\n }\n\n # \u8907\u5408\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\u3059\u308b\u691c\u7d22\n scope :by_author_and_date, ->(author_id, date) {\n where(author_id: author_id)\n .where('published_at >= ?', date)\n }\nend<\/pre>\n\n\n\n\u30ad\u30e3\u30c3\u30b7\u30e5\u6226\u7565\u3067\u30ec\u30b9\u30dd\u30f3\u30b9\u3092\u6539\u5584\u3059\u308b\u65b9\u6cd5<\/h2>\n\n\n\n1. \u30e2\u30c7\u30eb\u30ad\u30e3\u30c3\u30b7\u30e5<\/h3>\n\n\n\n# \u30ad\u30e3\u30c3\u30b7\u30e5\u30ad\u30fc\u306e\u8a2d\u5b9a\nclass Post < ApplicationRecord\n include ActiveModel::Caching\n\n # \u30bf\u30c3\u30c1\u30aa\u30d7\u30b7\u30e7\u30f3\u3067\u95a2\u9023\u30e2\u30c7\u30eb\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u3082\u66f4\u65b0\n belongs_to :user, touch: true\n\n # \u30ad\u30e3\u30c3\u30b7\u30e5\u30ad\u30fc\u306e\u30ab\u30b9\u30bf\u30de\u30a4\u30ba\n def cache_key\n \"#{super}-#{Digest::MD5.hexdigest(content)}\"\n end\nend<\/pre>\n\n\n\n2. \u30af\u30a8\u30ea\u30ad\u30e3\u30c3\u30b7\u30e5<\/h3>\n\n\n\n# find_by\u306e\u7d50\u679c\u3092\u30ad\u30e3\u30c3\u30b7\u30e5\ndef find_post_by_slug(slug)\n Rails.cache.fetch(\"post\/#{slug}\", expires_in: 12.hours) do\n Post.find_by(slug: slug)\n end\nend\n\n# \u8907\u96d1\u306a\u30af\u30a8\u30ea\u7d50\u679c\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\ndef trending_posts\n Rails.cache.fetch('trending_posts', expires_in: 1.hour) do\n Post.joins(:views)\n .group('posts.id')\n .order('COUNT(views.id) DESC')\n .limit(10)\n .to_a\n end\nend<\/pre>\n\n\n\n3. \u30ed\u30a6\u30ec\u30d9\u30eb\u30ad\u30e3\u30c3\u30b7\u30e5<\/h3>\n\n\n\nclass Post < ApplicationRecord\n # \u30ab\u30a6\u30f3\u30bf\u30fc\u30ad\u30e3\u30c3\u30b7\u30e5\n belongs_to :category, counter_cache: true\n\n # \u7b97\u51fa\u5024\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\n def cached_comments_count\n Rails.cache.fetch([self, 'comments_count']) do\n comments.count\n end\n end\nend<\/pre>\n\n\n\n4. \u30d5\u30e9\u30b0\u30e1\u30f3\u30c8\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u6700\u9069\u5316<\/h3>\n\n\n\n# \u30d3\u30e5\u30fc\u3067\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\n<% cache_if @post.cacheable?, @post do %>\n <article class=\"post\">\n <%= render @post.content %>\n\n <% cache @post.comments do %>\n <%= render @post.comments %>\n <% end %>\n <\/article>\n<% end %>\n\n# \u30ed\u30b7\u30a2\u30f3\u30c9\u30fc\u30eb\u30ad\u30e3\u30c3\u30b7\u30e5\n<% cache ['v1', @post] do %>\n <%= render @post %>\n <% cache ['v1', @post, :comments] do %>\n <%= render @post.comments %>\n <% end %>\n<% end %><\/pre>\n\n\n\n\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u76e3\u8996\u3068\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u30dd\u30a4\u30f3\u30c8<\/h3>\n\n\n\n\n- \u30af\u30a8\u30ea\u30ed\u30b0\u306e\u76e3\u8996<\/strong><\/li>\n<\/ol>\n\n\n\n
# development.rb\u3067\u306e\u8a2d\u5b9a\nconfig.after_initialize do\n Bullet.enable = true\n Bullet.alert = true\n Bullet.rails_logger = true\nend<\/pre>\n\n\n\n\n- \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8a08\u6e2c<\/strong><\/li>\n<\/ol>\n\n\n\n
# \u5b9f\u884c\u6642\u9593\u306e\u8a08\u6e2c\nActiveSupport::Notifications.subscribe('sql.active_record') do |*args|\n event = ActiveSupport::Notifications::Event.new(*args)\n if event.duration > 100\n Rails.logger.warn(\"Slow query detected: #{event.payload[:sql]}\")\n end\nend<\/pre>\n\n\n\n\u3053\u308c\u3089\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5927\u304d\u304f\u6539\u5584\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u53ef\u80fd\u6027\u306e\u3042\u308b\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
ActiveRecord\u306e\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3\u3068\u5bfe\u51e6\u6cd5<\/h1>\n\n\n\n\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u304c\u5897\u5927\u3059\u308b\u5371\u967a\u306a\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n1. \u5927\u91cf\u306e\u30ec\u30b3\u30fc\u30c9\u306e\u4e00\u62ec\u8aad\u307f\u8fbc\u307f<\/h3>\n\n\n\n# \u5371\u967a\u306a\u30d1\u30bf\u30fc\u30f3\nall_users = User.all.to_a # \u5168\u30ec\u30b3\u30fc\u30c9\u3092\u30e1\u30e2\u30ea\u306b\u5c55\u958b\n\n# \u63a8\u5968\u3055\u308c\u308b\u5b9f\u88c5\nUser.find_each do |user|\n # \u4e00\u5b9a\u6570\u305a\u3064\u51e6\u7406\nend\n\n# \u30d0\u30c3\u30c1\u30b5\u30a4\u30ba\u306e\u6307\u5b9a\nUser.find_each(batch_size: 100) do |user|\n # \u51e6\u7406\nend<\/pre>\n\n\n\n2. \u4e0d\u5fc5\u8981\u306a\u30ab\u30e9\u30e0\u306e\u8aad\u307f\u8fbc\u307f<\/h3>\n\n\n\n# \u30e1\u30e2\u30ea\u3092\u7121\u99c4\u306b\u4f7f\u7528\nusers = User.all.select(:id, :name, :email, :created_at, :updated_at)\n\n# \u5fc5\u8981\u306a\u30ab\u30e9\u30e0\u306e\u307f\u6307\u5b9a\nusers = User.select(:id, :name) # \u5fc5\u8981\u6700\u5c0f\u9650\u306e\u30ab\u30e9\u30e0\n\n# \u7279\u5b9a\u306e\u30ab\u30e9\u30e0\u3092\u9664\u5916\nusers = User.select(User.attribute_names - ['huge_data_column'])<\/pre>\n\n\n\n3. \u5de8\u5927\u306a\u914d\u5217\u306e\u751f\u6210<\/h3>\n\n\n\n# \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u304c\u5897\u5927\u3059\u308b\u5b9f\u88c5\ndef self.all_user_names\n pluck(:name) # \u5168\u30e6\u30fc\u30b6\u30fc\u540d\u3092\u914d\u5217\u3068\u3057\u3066\u4fdd\u6301\n\n# \u30e1\u30e2\u30ea\u52b9\u7387\u306e\u826f\u3044\u5b9f\u88c5\ndef self.process_user_names\n pluck(:name).find_each do |name|\n yield name\n end\nend<\/pre>\n\n\n\n\u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u3092\u5f15\u304d\u8d77\u3053\u3059\u5178\u578b\u7684\u306a\u30df\u30b9<\/h2>\n\n\n\n1. \u4e0d\u9069\u5207\u306a\u30ed\u30c3\u30af\u9806\u5e8f<\/h3>\n\n\n\n# \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u306e\u5371\u967a\u304c\u3042\u308b\u30b3\u30fc\u30c9\ndef transfer_money(from_account, to_account, amount)\n from_account.with_lock do\n to_account.with_lock do\n # \u51e6\u7406\n end\n end\nend\n\n# \u6539\u5584\u3055\u308c\u305f\u5b9f\u88c5\uff08ID\u3067\u30ed\u30c3\u30af\u9806\u5e8f\u3092\u56fa\u5b9a\uff09\ndef transfer_money(from_account, to_account, amount)\n first, second = [from_account, to_account].sort_by(&:id)\n first.with_lock do\n second.with_lock do\n # \u51e6\u7406\n end\n end\nend<\/pre>\n\n\n\n2. \u9577\u6642\u9593\u306e\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h3>\n\n\n\n# \u554f\u984c\u306e\u3042\u308b\u5b9f\u88c5\ndef process_large_data\n Transaction.transaction do\n huge_data.each do |data|\n # \u6642\u9593\u306e\u304b\u304b\u308b\u51e6\u7406\n end\n end\nend\n\n# \u6539\u5584\u3055\u308c\u305f\u5b9f\u88c5\ndef process_large_data\n huge_data.each_slice(100) do |batch|\n Transaction.transaction do\n batch.each do |data|\n # \u51e6\u7406\n end\n end\n end\nend<\/pre>\n\n\n\n3. \u4e0d\u9069\u5207\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u8a2d\u8a08<\/h3>\n\n\n\n# \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u3092\u8a98\u767a\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308b\u66f4\u65b0\nclass AddIndexWithoutLockStrategy < ActiveRecord::Migration[7.0]\n def change\n add_index :large_table, :column_name # \u30c6\u30fc\u30d6\u30eb\u30ed\u30c3\u30af\u304c\u767a\u751f\n\n # \u4ee3\u308f\u308a\u306b\n add_index :large_table, :column_name, algorithm: :concurrently\n end\nend<\/pre>\n\n\n\n\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3\u3092\u56de\u907f\u3059\u308b\u305f\u3081\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n\n\n\n\n- \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n
\n- \u5fc5\u8981\u306a\u30ab\u30e9\u30e0\u306e\u307f\u3092\u9078\u629e<\/li>\n\n\n\n
- \u30d0\u30c3\u30c1\u51e6\u7406\u306e\u6d3b\u7528<\/li>\n\n\n\n
- \u30b9\u30c8\u30ea\u30fc\u30df\u30f3\u30b0\u51e6\u7406\u306e\u5229\u7528<\/li>\n<\/ul>\n\n\n\n
# \u30b9\u30c8\u30ea\u30fc\u30df\u30f3\u30b0\u51e6\u7406\u306e\u4f8b\nrequire 'csv'\n\nCSV.open('users.csv', 'w') do |csv|\n User.select(:id, :name).find_each do |user|\n csv << [user.id, user.name]\n end\nend<\/pre>\n\n\n\n\n- \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u5bfe\u7b56<\/strong><\/li>\n<\/ol>\n\n\n\n
\n- \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u7bc4\u56f2\u3092\u6700\u5c0f\u9650\u306b<\/li>\n\n\n\n
- \u30ed\u30c3\u30af\u9806\u5e8f\u306e\u4e00\u8cab\u6027\u7dad\u6301<\/li>\n\n\n\n
- \u9069\u5207\u306a\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u8a2d\u5b9a<\/li>\n<\/ul>\n\n\n\n
# \u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u8a2d\u5b9a\u306e\u4f8b\nconfig.active_record.lock_timeout = 5.seconds\nconfig.active_record.statement_timeout = 10.seconds<\/pre>\n\n\n\n\n- \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0<\/strong><\/li>\n<\/ol>\n\n\n\n
# \u30af\u30a8\u30ea\u5b9f\u884c\u6642\u9593\u306e\u76e3\u8996\nActiveSupport::Notifications.subscribe('sql.active_record') do |*args|\n event = ActiveSupport::Notifications::Event.new(*args)\n if event.duration > 100\n Rails.logger.warn(\"Slow query detected: #{event.payload[:sql]}\")\n Rails.logger.warn(\"Duration: #{event.duration}ms\")\n end\nend<\/pre>\n\n\n\n\u3053\u308c\u3089\u306e\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3\u3092\u7406\u89e3\u3057\u3001\u9069\u5207\u306a\u5bfe\u51e6\u6cd5\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5b89\u5b9a\u3057\u305f\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u904b\u7528\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3055\u3089\u306b\u9ad8\u5ea6\u306aActiveRecord\u306e\u30c6\u30af\u30cb\u30c3\u30af\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\u5b9f\u52d9\u3067\u4f7f\u3048\u308b\u9ad8\u5ea6\u306aActiveRecord\u30c6\u30af\u30cb\u30c3\u30af<\/h1>\n\n\n\n\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u95a2\u9023\u4ed8\u3051\u306e\u6d3b\u7528\u30b7\u30fc\u30f3<\/h2>\n\n\n\n1. \u901a\u77e5\u30b7\u30b9\u30c6\u30e0\u306e\u5b9f\u88c5<\/h3>\n\n\n\n# app\/models\/notification.rb\nclass Notification < ApplicationRecord\n belongs_to :notifiable, polymorphic: true\n belongs_to :recipient, class_name: 'User'\n\n scope :unread, -> { where(read_at: nil) }\n scope :recent, -> { order(created_at: :desc) }\nend\n\n# app\/models\/comment.rb\nclass Comment < ApplicationRecord\n has_many :notifications, as: :notifiable, dependent: :destroy\n\n after_create :create_notification\n\n private\n\n def create_notification\n Notification.create(\n notifiable: self,\n recipient: post.user,\n action: 'commented',\n message: \"#{user.name}\u304c\u3042\u306a\u305f\u306e\u6295\u7a3f\u306b\u30b3\u30e1\u30f3\u30c8\u3057\u307e\u3057\u305f\"\n )\n end\nend\n\n# app\/models\/like.rb\nclass Like < ApplicationRecord\n has_many :notifications, as: :notifiable, dependent: :destroy\n\n after_create :create_notification\nend<\/pre>\n\n\n\n2. \u6dfb\u4ed8\u30d5\u30a1\u30a4\u30eb\u7ba1\u7406\u30b7\u30b9\u30c6\u30e0<\/h3>\n\n\n\n# app\/models\/attachment.rb\nclass Attachment < ApplicationRecord\n belongs_to :attachable, polymorphic: true\n\n has_one_attached :file\n\n validates :file, presence: true\n validates :file, content_type: { \n in: %w[image\/jpeg image\/png application\/pdf],\n message: '\u8a31\u53ef\u3055\u308c\u3066\u3044\u306a\u3044\u30d5\u30a1\u30a4\u30eb\u5f62\u5f0f\u3067\u3059'\n }\nend\n\n# \u4f7f\u7528\u4f8b\nclass Report < ApplicationRecord\n has_many :attachments, as: :attachable, dependent: :destroy\n accepts_nested_attributes_for :attachments, allow_destroy: true\nend<\/pre>\n\n\n\n\u30b5\u30fc\u30d3\u30b9\u30af\u30e9\u30b9\u3068\u306e\u52b9\u679c\u7684\u306a\u4f75\u7528\u65b9\u6cd5<\/h2>\n\n\n\n1. \u8907\u96d1\u306a\u696d\u52d9\u30ed\u30b8\u30c3\u30af\u306e\u5206\u96e2<\/h3>\n\n\n\n# app\/services\/order_processor.rb\nclass OrderProcessor\n def initialize(order)\n @order = order\n end\n\n def process\n ApplicationRecord.transaction do\n update_inventory\n process_payment\n send_notifications\n end\n rescue => e\n handle_error(e)\n false\n end\n\n private\n\n def update_inventory\n @order.order_items.each do |item|\n item.product.with_lock do\n raise InsufficientStock unless item.product.sufficient_stock?(item.quantity)\n item.product.decrease_stock(item.quantity)\n end\n end\n end\n\n def process_payment\n payment = Payment.create!(\n order: @order,\n amount: @order.total_amount\n )\n PaymentGateway.new(payment).process\n end\nend\n\n# \u4f7f\u7528\u4f8b\nclass OrdersController < ApplicationController\n def create\n @order = Order.new(order_params)\n\n if OrderProcessor.new(@order).process\n redirect_to @order, notice: '\u6ce8\u6587\u304c\u5b8c\u4e86\u3057\u307e\u3057\u305f'\n else\n render :new\n end\n end\nend<\/pre>\n\n\n\n2. \u30d5\u30a9\u30fc\u30e0\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u306e\u9023\u643a<\/h3>\n\n\n\n# app\/forms\/user_registration_form.rb\nclass UserRegistrationForm\n include ActiveModel::Model\n\n attr_accessor :email, :password, :terms_accepted\n\n validates :email, presence: true, format: { with: URI::MailTo::EMAIL_REGEXP }\n validates :password, length: { minimum: 8 }\n validates :terms_accepted, acceptance: true\n\n def save\n return false unless valid?\n\n User.transaction do\n user = User.create!(\n email: email,\n password: password\n )\n Profile.create!(user: user)\n UserMailer.welcome(user).deliver_later\n end\n rescue ActiveRecord::RecordInvalid\n false\n end\nend<\/pre>\n\n\n\n\u30c6\u30b9\u30c8\u99c6\u52d5\u958b\u767a\u306b\u304a\u3051\u308bActiveRecord\u306e\u6271\u3044\u65b9<\/h2>\n\n\n\n1. \u30d5\u30a1\u30af\u30c8\u30ea\u3092\u6d3b\u7528\u3057\u305f\u30c6\u30b9\u30c8<\/h3>\n\n\n\n# spec\/factories\/users.rb\nFactoryBot.define do\n factory :user do\n sequence(:email) { |n| \"user#{n}@example.com\" }\n password { \"password123\" }\n\n # \u95a2\u9023\u4ed8\u3051\u3092\u6301\u3064\u30d5\u30a1\u30af\u30c8\u30ea\n factory :user_with_posts do\n transient do\n posts_count { 5 }\n end\n\n after(:create) do |user, evaluator|\n create_list(:post, evaluator.posts_count, user: user)\n end\n end\n end\nend\n\n# spec\/models\/user_spec.rb\nRSpec.describe User, type: :model do\n describe '#active_posts' do\n let(:user) { create(:user_with_posts) }\n\n before do\n user.posts.first.update(status: 'archived')\n end\n\n it 'returns only active posts' do\n expect(user.active_posts.count).to eq 4\n end\n end\nend<\/pre>\n\n\n\n2. \u30e2\u30c3\u30af\u3068\u30b9\u30bf\u30d6\u306e\u9069\u5207\u306a\u4f7f\u7528<\/h3>\n\n\n\nRSpec.describe OrderProcessor do\n let(:order) { create(:order) }\n let(:processor) { OrderProcessor.new(order) }\n\n describe '#process' do\n before do\n allow(PaymentGateway).to receive(:new)\n .and_return(double(process: true))\n end\n\n it 'processes the order successfully' do\n expect(processor.process).to be true\n end\n\n context 'when stock is insufficient' do\n before do\n allow_any_instance_of(Product)\n .to receive(:sufficient_stock?)\n .and_return(false)\n end\n\n it 'fails to process the order' do\n expect(processor.process).to be false\n end\n end\n end\nend<\/pre>\n\n\n\n3. SharedExamples\u306e\u6d3b\u7528<\/h3>\n\n\n\nRSpec.shared_examples 'softly deletable' do\n let(:model) { described_class }\n\n it 'can be soft deleted' do\n instance = create(model.to_s.underscore)\n expect {\n instance.soft_delete\n }.to change { instance.deleted_at }.from(nil)\n end\n\n it 'scopes active records' do\n active = create(model.to_s.underscore)\n deleted = create(model.to_s.underscore, deleted_at: Time.current)\n\n expect(model.active).to include(active)\n expect(model.active).not_to include(deleted)\n end\nend\n\nRSpec.describe Post do\n it_behaves_like 'softly deletable'\nend<\/pre>\n\n\n\n\u3053\u308c\u3089\u306e\u9ad8\u5ea6\u306a\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u4fdd\u5b88\u6027\u304c\u9ad8\u304f\u3001\u30c6\u30b9\u30c8\u53ef\u80fd\u306a\u5b9f\u88c5\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001ActiveRecord\u306e\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u3068\u30c7\u30d0\u30c3\u30b0\u624b\u6cd5\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
ActiveRecord\u306e\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u3068\u30c7\u30d0\u30c3\u30b0\u624b\u6cd5<\/h1>\n\n\n\n\u30b9\u30ed\u30fc\u30af\u30a8\u30ea\u3092\u7279\u5b9a\u3057\u3066\u6539\u5584\u3059\u308b\u624b\u9806<\/h2>\n\n\n\n1. \u30ed\u30b0\u306e\u8a2d\u5b9a\u3068\u89e3\u6790<\/h3>\n\n\n\n# config\/environments\/production.rb\nconfig.active_record.verbose_query_logs = true\nconfig.logger = ActiveSupport::Logger.new(\"log\/production.log\")\n\n# \u30b9\u30ed\u30fc\u30af\u30a8\u30ea\u306e\u30ed\u30b0\u8a2d\u5b9a\nActiveRecord::Base.logger = ActiveSupport::TaggedLogging.new(\n ActiveSupport::Logger.new(\"log\/slow_queries.log\")\n)\n\n# \u30af\u30a8\u30ea\u5b9f\u884c\u6642\u9593\u306e\u76e3\u8996\nActiveSupport::Notifications.subscribe('sql.active_record') do |*args|\n event = ActiveSupport::Notifications::Event.new(*args)\n if event.duration > 1000 # 1\u79d2\u4ee5\u4e0a\u304b\u304b\u308b\u30af\u30a8\u30ea\n Rails.logger.warn(<<~SQL)\n Slow Query Detected:\n Duration: #{event.duration}ms\n SQL: #{event.payload[:sql]}\n Location: #{event.payload[:name]}\n SQL\n end\nend<\/pre>\n\n\n\n2. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u5206\u6790\u30c4\u30fc\u30eb\u306e\u6d3b\u7528<\/h3>\n\n\n\n# Gemfile\ngroup :development do\n gem 'rack-mini-profiler'\n gem 'bullet'\n gem 'rails-erd' # ER\u30c0\u30a4\u30a2\u30b0\u30e9\u30e0\u751f\u6210\nend\n\n# config\/environments\/development.rb\nconfig.after_initialize do\n Bullet.enable = true\n Bullet.alert = true\n Bullet.rails_logger = true\n Bullet.add_footer = true\n\n Bullet.unused_eager_loading_enable = false\nend<\/pre>\n\n\n\n\u672c\u756a\u74b0\u5883\u3067\u306e\u5b89\u5168\u306a\u30c7\u30d0\u30c3\u30b0\u65b9\u6cd5<\/h2>\n\n\n\n1. \u5b89\u5168\u306a\u30c7\u30d0\u30c3\u30b0\u60c5\u5831\u306e\u53ce\u96c6<\/h3>\n\n\n\n# app\/controllers\/application_controller.rb\nclass ApplicationController < ActionController::Base\n around_action :catch_and_log_exceptions\n\n private\n\n def catch_and_log_exceptions\n yield\n rescue => error\n ErrorLogger.log(\n error: error,\n controller: controller_name,\n action: action_name,\n params: filtered_params,\n user: current_user&.id\n )\n raise\n end\n\n def filtered_params\n params.except('controller', 'action').to_unsafe_h\n end\nend\n\n# lib\/error_logger.rb\nclass ErrorLogger\n def self.log(error:, **context)\n Rails.logger.error(<<~ERROR)\n Exception: #{error.class}\n Message: #{error.message}\n Context: #{context}\n Backtrace:\n #{error.backtrace&.first(10)&.join(\"\\n\")}\n ERROR\n end\nend<\/pre>\n\n\n\n2. \u30c7\u30d0\u30c3\u30b0\u30e2\u30fc\u30c9\u306e\u5b9f\u88c5<\/h3>\n\n\n\n# config\/initializers\/debug_mode.rb\nmodule DebugMode\n mattr_accessor :enabled\n\n def self.enable!\n self.enabled = true\n ActiveRecord::Base.logger = Logger.new(STDOUT)\n end\n\n def self.disable!\n self.enabled = false\n ActiveRecord::Base.logger = Rails.logger\n end\nend\n\n# \u4f7f\u7528\u4f8b\nclass ComplexQuery\n def execute\n if DebugMode.enabled\n log_query_execution do\n perform_query\n end\n else\n perform_query\n end\n end\n\n private\n\n def log_query_execution\n start_time = Time.current\n result = yield\n duration = Time.current - start_time\n\n Rails.logger.info(<<~DEBUG)\n Query Execution:\n Duration: #{duration}s\n Result Count: #{result.size}\n DEBUG\n\n result\n end\nend<\/pre>\n\n\n\n\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n\n\n\n1. \u30e1\u30c8\u30ea\u30af\u30b9\u306e\u53ce\u96c6<\/h3>\n\n\n\n# config\/initializers\/metrics.rb\nmodule ActiveRecordMetrics\n def self.included(base)\n base.extend(ClassMethods)\n\n base.class_eval do\n after_create :track_creation\n after_update :track_update\n after_destroy :track_deletion\n end\n end\n\n module ClassMethods\n def track_metrics!\n include ActiveRecordMetrics\n end\n end\n\n private\n\n def track_creation\n StatsD.increment(\"#{self.class.name.underscore}.created\")\n end\n\n def track_update\n StatsD.increment(\"#{self.class.name.underscore}.updated\")\n end\n\n def track_deletion\n StatsD.increment(\"#{self.class.name.underscore}.deleted\")\n end\nend\n\n# \u30e2\u30c7\u30eb\u3067\u306e\u4f7f\u7528\nclass User < ApplicationRecord\n track_metrics!\nend<\/pre>\n\n\n\n2. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0<\/h3>\n\n\n\nmodule QueryMonitoring\n def self.included(base)\n base.extend(ClassMethods)\n end\n\n module ClassMethods\n def monitor_queries!\n around_query do |*, &block|\n start_time = Time.current\n result = block.call\n duration = Time.current - start_time\n\n if duration > threshold\n alert_slow_query(duration)\n end\n\n result\n end\n end\n\n private\n\n def threshold\n ENV.fetch('QUERY_THRESHOLD', 1.0).to_f\n end\n\n def alert_slow_query(duration)\n SlackNotifier.notify(\n channel: '#performance',\n text: \"Slow query detected (#{duration}s)\"\n )\n end\n end\nend<\/pre>\n\n\n\n\u3053\u308c\u3089\u306e\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u3068\u30c7\u30d0\u30c3\u30b0\u624b\u6cd5\u3092\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u554f\u984c\u306e\u65e9\u671f\u767a\u898b\u3068\u8fc5\u901f\u306a\u5bfe\u5fdc\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u307e\u3067\u306e\u5185\u5bb9\u3092\u8e0f\u307e\u3048\u305f\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306b\u3064\u3044\u3066\u307e\u3068\u3081\u307e\u3059\u3002<\/p>\n\n\n\n
ActiveRecord\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u307e\u3068\u3081<\/h1>\n\n\n\n\u73fe\u5834\u3067\u4f7f\u3048\u308b7\u3064\u306e\u91cd\u8981\u306a\u8a2d\u8a08\u6307\u91dd<\/h2>\n\n\n\n1. \u30e2\u30c7\u30eb\u8a2d\u8a08\u306e\u539f\u5247<\/h3>\n\n\n\n\n- \u5358\u4e00\u8cac\u4efb\u306e\u539f\u5247\u3092\u5b88\u308b<\/strong><\/li>\n<\/ul>\n\n\n\n
# \u60aa\u3044\u4f8b\uff1a\u30e2\u30c7\u30eb\u306b\u591a\u3059\u304e\u308b\u8cac\u4efb\u304c\u3042\u308b\nclass User < ApplicationRecord\n # \u8a8d\u8a3c\u3001\u30d7\u30ed\u30d5\u30a3\u30fc\u30eb\u3001\u6c7a\u6e08\u306a\u3069\u591a\u304f\u306e\u8cac\u4efb\u3092\u6301\u3064\nend\n\n# \u826f\u3044\u4f8b\uff1a\u8cac\u4efb\u3092\u9069\u5207\u306b\u5206\u5272\nclass User < ApplicationRecord\n has_one :profile\n has_one :payment_setting\n\n # \u8a8d\u8a3c\u95a2\u9023\u306e\u51e6\u7406\n include Authenticatable\n\n # \u30d7\u30ed\u30d5\u30a3\u30fc\u30eb\u95a2\u9023\u306e\u51e6\u7406\n delegate :full_name, :avatar_url, to: :profile\nend<\/pre>\n\n\n\n2. \u30af\u30a8\u30ea\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/h3>\n\n\n\n\n- \u5fc5\u8981\u6700\u5c0f\u9650\u306e\u30c7\u30fc\u30bf\u3060\u3051\u3092\u53d6\u5f97\u3059\u308b<\/strong><\/li>\n<\/ul>\n\n\n\n
# \u57fa\u672c\u7684\u306a\u30b9\u30b3\u30fc\u30d7\u306e\u5b9a\u7fa9\nclass Article < ApplicationRecord\n scope :published_with_author, -> {\n select('articles.id, articles.title, users.name as author_name')\n .joins(:user)\n .where(published: true)\n }\n\n # \u30ab\u30b9\u30bf\u30e0\u30b9\u30b3\u30fc\u30d7\u30d3\u30eb\u30c0\u30fc\n scope :with_required_columns, ->(columns) {\n select(Array(columns))\n }\nend<\/pre>\n\n\n\n3. \u30d0\u30c3\u30c1\u51e6\u7406\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9<\/h3>\n\n\n\n\n- \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5<\/strong><\/li>\n<\/ul>\n\n\n\n
class BatchProcessor\n def self.process_users\n User.find_each(batch_size: 100) do |user|\n UserStatisticsCalculator.new(user).calculate\n rescue => e\n Rails.logger.error(\"Failed to process user #{user.id}: #{e.message}\")\n next\n end\n end\nend<\/pre>\n\n\n\n4. \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u7ba1\u7406<\/h3>\n\n\n\n\n- \u9069\u5207\u306a\u7c92\u5ea6\u3067\u306e\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u5236\u5fa1<\/strong><\/li>\n<\/ul>\n\n\n\n