{"id":1219,"date":"2025-03-24T08:52:34","date_gmt":"2025-03-23T23:52:34","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=1219"},"modified":"2025-03-24T08:52:34","modified_gmt":"2025-03-23T23:52:34","slug":"%e3%80%90%e4%bf%9d%e5%ad%98%e7%89%88%e3%80%91rails-activerecord%e3%81%ae%e4%bd%bf%e3%81%84%e6%96%b9%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%892024%ef%bc%9a7%e3%81%a4%e3%81%ae%e9%87%8d%e8%a6%81","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=1219","title":{"rendered":"\u3010\u4fdd\u5b58\u7248\u3011Rails ActiveRecord\u306e\u4f7f\u3044\u65b9\u5b8c\u5168\u30ac\u30a4\u30c92024\uff1a7\u3064\u306e\u91cd\u8981\u6a5f\u80fd\u3068\u5b9f\u8df5\u7684\u306a\u6d3b\u7528\u6cd5"},"content":{"rendered":"\n<div class=\"toc\"><br \/>\n<b>Warning<\/b>:  Undefined array key \"is_admin\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>116<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_category_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>121<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>128<\/b><br \/>\n    <div id=\"toc_container\" class=\"sgb-toc--bullets js-smooth-scroll\" data-dialog-title=\"\u76ee\u6b21\">\n      <p class=\"toc_title\">\u76ee\u6b21 <\/p>\n      <ul class=\"toc_list\">  <li class=\"first\">    <a href=\"#i-0\">ActiveRecord\u3068\u306f\uff1fRails\u3067\u306e\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u306e\u57fa\u790e<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-1\">ActiveRecord\u304c\u89e3\u6c7a\u3059\u308b3\u3064\u306e\u958b\u767a\u8ab2\u984c<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-2\">ORM\u306e\u4ed5\u7d44\u307f\u3068ActiveRecord\u306e\u7279\u5fb4<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-7\">ActiveRecord\u30e2\u30c7\u30eb\u306e\u57fa\u672c\u8a2d\u5b9a\u3068\u6d3b\u7528\u6cd5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-8\">\u30e2\u30c7\u30eb\u30af\u30e9\u30b9\u306e\u4f5c\u6210\u3068\u30b9\u30ad\u30fc\u30de\u5b9a\u7fa9\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-12\">\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3068\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-17\">ActiveRecord\u3067\u5b9f\u73fe\u3059\u308b\u9ad8\u5ea6\u306a\u30c7\u30fc\u30bf\u64cd\u4f5c<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-18\">\u8907\u96d1\u306a\u6761\u4ef6\u3067\u306e\u30ec\u30b3\u30fc\u30c9\u691c\u7d22\u3068\u7d5e\u308a\u8fbc\u307f\u624b\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-22\">\u30a2\u30bd\u30b7\u30a8\u30fc\u30b7\u30e7\u30f3\u3092\u6d3b\u7528\u3057\u305f\u30e2\u30c7\u30eb\u9593\u306e\u95a2\u4fc2\u6027\u7ba1\u7406<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-27\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3057\u305fActiveRecord\u306e\u4f7f\u3044\u65b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-28\">N+1\u554f\u984c\u306e\u7406\u89e3\u3068\u52b9\u7387\u7684\u306a\u89e3\u6c7a\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-31\">\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3068\u30af\u30a8\u30ea\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-36\">ActiveRecord\u3092\u4f7f\u3063\u305f\u5b9f\u8df5\u7684\u306a\u958b\u767a\u30c6\u30af\u30cb\u30c3\u30af<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-37\">\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-41\">\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u51e6\u7406\u306e\u52b9\u7387\u5316\u624b\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-46\">ActiveRecord\u306e\u30c6\u30b9\u30c8\u99c6\u52d5\u958b\u767a<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-47\">\u30e2\u30c7\u30eb\u306e\u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u4f5c\u6210\u624b\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-50\">\u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u4f5c\u6210\u3068\u30d5\u30a1\u30af\u30c8\u30ea\u306e\u6d3b\u7528\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-54\">ActiveRecord\u306e\u904b\u7528\u7ba1\u7406\u3068\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-55\">\u4e00\u822c\u7684\u306a\u30a8\u30e9\u30fc\u30d1\u30bf\u30fc\u30f3\u3068\u89e3\u6c7a\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-59\">\u30c7\u30d0\u30c3\u30b0\u3068\u30ed\u30b0\u89e3\u6790\u306e\u52b9\u679c\u7684\u306a\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li><\/ul>\n      <a href=\"#\" class=\"sgb-toc-button js-toc-button\" rel=\"nofollow\" data-open-dialog=\"true\"><i class=\"fa fa-list\"><\/i><span class=\"sgb-toc-button__text\">\u76ee\u6b21\u3078<\/span><\/a>\n    <\/div><\/div><h2 class=\"wp-block-heading\" id=\"i-0\">ActiveRecord\u3068\u306f\uff1fRails\u3067\u306e\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u306e\u57fa\u790e<\/h2>\n\n\n\n<p>ActiveRecord\u306f\u3001Rails\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306b\u304a\u3051\u308b\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u306e\u4e2d\u6838\u3092\u62c5\u3046\u30e9\u30a4\u30d6\u30e9\u30ea\u3067\u3059\u3002\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u30c6\u30fc\u30d6\u30eb\u3084\u30ec\u30b3\u30fc\u30c9\u3092Ruby\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u3057\u3066\u6271\u3048\u308b\u3088\u3046\u306b\u3059\u308b\u300cORM\uff08Object-Relational Mapping\uff09\u300d\u306e\u5b9f\u88c5\u3068\u3057\u3066\u3001Rails\u306e\u91cd\u8981\u306a\u6a5f\u80fd\u306e\u4e00\u3064\u3068\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-1\">ActiveRecord\u304c\u89e3\u6c7a\u3059\u308b3\u3064\u306e\u958b\u767a\u8ab2\u984c<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>SQL\u306e\u8907\u96d1\u306a\u8a18\u8ff0\u304b\u3089\u306e\u89e3\u653e<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5f93\u6765\u306eSQL\u8a18\u8ff0<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   SELECT * FROM users WHERE age &gt;= 20 AND status = 'active' ORDER BY created_at DESC;<\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>ActiveRecord\u3067\u306e\u8a18\u8ff0<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   User.where('age &gt;= ?', 20).where(status: 'active').order(created_at: :desc)<\/pre>\n\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001Ruby\u306e\u30e1\u30bd\u30c3\u30c9\u30c1\u30a7\u30fc\u30f3\u3067SQL\u3092\u8868\u73fe\u3067\u304d\u308b\u305f\u3081\u3001\u53ef\u8aad\u6027\u304c\u9ad8\u304f\u4fdd\u5b88\u3057\u3084\u3059\u3044\u30b3\u30fc\u30c9\u304c\u66f8\u3051\u307e\u3059\u3002<\/p>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>\u30c7\u30fc\u30bf\u306e\u6574\u5408\u6027\u7ba1\u7406\u306e\u81ea\u52d5\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306b\u3088\u308b\u30c7\u30fc\u30bf\u30c1\u30a7\u30c3\u30af<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   class User &lt; ApplicationRecord\n     validates :email, presence: true, uniqueness: true\n     validates :age, numericality: { greater_than_or_equal_to: 0 }\n   end<\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30ea\u30ec\u30fc\u30b7\u30e7\u30f3\u30b7\u30c3\u30d7\u306e\u81ea\u52d5\u7ba1\u7406<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   class User &lt; ApplicationRecord\n     has_many :posts, dependent: :destroy\n     has_one :profile\n   end<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30af\u30ed\u30b9\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u306e\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u5bfe\u5fdc<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7570\u306a\u308b\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\uff08MySQL\u3001PostgreSQL\u3001SQLite\uff09\u3067\u3082\u540c\u3058\u30b3\u30fc\u30c9\u304c\u52d5\u4f5c<\/li>\n\n\n\n<li>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u56fa\u6709\u306e\u6a5f\u80fd\u3082\u30a2\u30c0\u30d7\u30bf\u30fc\u3092\u901a\u3058\u3066\u7d71\u4e00\u7684\u306b\u5229\u7528\u53ef\u80fd<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">ORM\u306e\u4ed5\u7d44\u307f\u3068ActiveRecord\u306e\u7279\u5fb4<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-3\">1. \u30e2\u30c7\u30eb\u3068\u30c6\u30fc\u30d6\u30eb\u306e\u81ea\u52d5\u30de\u30c3\u30d4\u30f3\u30b0<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># app\/models\/user.rb\nclass User &lt; ApplicationRecord\nend\n\n# \u3053\u306e\u30e2\u30c7\u30eb\u3067\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u304c\u53ef\u80fd\nuser = User.new(name: \"\u5c71\u7530\u592a\u90ce\", email: \"yamada@example.com\")\nuser.save  # =&gt; SQL\u306eINSERT\u6587\u304c\u81ea\u52d5\u751f\u6210\u3055\u308c\u5b9f\u884c\u3055\u308c\u308b<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-4\">2. \u898f\u7d04\u512a\u5148\u306e\u8a2d\u8a08\u601d\u60f3<\/h4>\n\n\n\n<p>ActiveRecord\u306f\u300cConvention over Configuration\uff08\u898f\u7d04\u512a\u5148\uff09\u300d\u306e\u601d\u60f3\u306b\u57fa\u3065\u3044\u3066\u3044\u307e\u3059\uff1a<\/p>\n\n\n<div id=\"id-28cc71b9-0933-4096-ba9b-c2a37f64f5bd\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u30e2\u30c7\u30eb\u540d\uff08\u5358\u6570\u5f62\uff09<\/th><th>\u30c6\u30fc\u30d6\u30eb\u540d\uff08\u8907\u6570\u5f62\uff09<\/th><th>\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>User<\/td><td>users<\/td><td>class User &lt; ApplicationRecord<\/td><\/tr><tr><td>Person<\/td><td>people<\/td><td>class Person &lt; ApplicationRecord<\/td><\/tr><tr><td>Category<\/td><td>categories<\/td><td>class Category &lt; ApplicationRecord<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<h4 class=\"wp-block-heading\" id=\"i-5\">3. \u8c4a\u5bcc\u306a\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u6a5f\u80fd<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class User &lt; ApplicationRecord\n  before_save :encrypt_password\n  after_create :send_welcome_email\n\n  private\n\n  def encrypt_password\n    self.password = BCrypt::Password.create(password) if password.present?\n  end\n\n  def send_welcome_email\n    UserMailer.welcome_email(self).deliver_later\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-6\">4. \u30e1\u30bf\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u3088\u308b\u52d5\u7684\u6a5f\u80fd<\/h4>\n\n\n\n<p>ActiveRecord\u306f\u3001\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u30b9\u30ad\u30fc\u30de\u3092\u8aad\u307f\u53d6\u3063\u3066\u81ea\u52d5\u7684\u306b\u30e2\u30c7\u30eb\u306e\u30e1\u30bd\u30c3\u30c9\u3092\u751f\u6210\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># schema.rb\ncreate_table :users do |t|\n  t.string :name\n  t.string :email\n  t.timestamps\nend\n\n# \u81ea\u52d5\u7684\u306b\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30e1\u30bd\u30c3\u30c9\u304c\u4f7f\u3048\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\nuser = User.new\nuser.name = \"\u9234\u6728\u4e00\u90ce\"    # name= \u30e1\u30bd\u30c3\u30c9\nuser.email = \"suzuki@example.com\"  # email= \u30e1\u30bd\u30c3\u30c9\nuser.name  # =&gt; \"\u9234\u6728\u4e00\u90ce\"    # name \u30e1\u30bd\u30c3\u30c9<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u7279\u5fb4\u306b\u3088\u308a\u3001ActiveRecord\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u5229\u70b9\u3092\u958b\u767a\u8005\u306b\u3082\u305f\u3089\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u958b\u767a\u901f\u5ea6\u306e\u5411\u4e0a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5b9a\u578b\u7684\u306a\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u51e6\u7406\u306e\u30b3\u30fc\u30c9\u91cf\u3092\u5927\u5e45\u306b\u524a\u6e1b<\/li>\n\n\n\n<li>\u76f4\u611f\u7684\u306aAPI\u306b\u3088\u308b\u7d20\u65e9\u3044\u5b9f\u88c5<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30b3\u30fc\u30c9\u306e\u54c1\u8cea\u5411\u4e0a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e00\u8cab\u6027\u306e\u3042\u308b\u8a18\u8ff0\u65b9\u6cd5\u306e\u5f37\u5236<\/li>\n\n\n\n<li>\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306b\u3088\u308b\u30c7\u30fc\u30bf\u54c1\u8cea\u306e\u78ba\u4fdd<\/li>\n\n\n\n<li>\u30c6\u30b9\u30c8\u306e\u3057\u3084\u3059\u3055<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u4fdd\u5b88\u6027\u306e\u5411\u4e0a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u64cd\u4f5c\u306e\u62bd\u8c61\u5316\u306b\u3088\u308b\u5909\u66f4\u5bb9\u6613\u6027<\/li>\n\n\n\n<li>\u7d71\u4e00\u3055\u308c\u305f\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u30b9\u30bf\u30a4\u30eb<\/li>\n<\/ul>\n\n\n\n<p>ActiveRecord\u306e\u57fa\u672c\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001Rails\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u52b9\u7387\u7684\u306a\u958b\u767a\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u57fa\u790e\u77e5\u8b58\u3092\u6d3b\u304b\u3057\u305fActiveRecord\u30e2\u30c7\u30eb\u306e\u5177\u4f53\u7684\u306a\u8a2d\u5b9a\u65b9\u6cd5\u3068\u6d3b\u7528\u6cd5\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-7\">ActiveRecord\u30e2\u30c7\u30eb\u306e\u57fa\u672c\u8a2d\u5b9a\u3068\u6d3b\u7528\u6cd5<\/h2>\n\n\n\n<p>ActiveRecord\u30e2\u30c7\u30eb\u3092\u52b9\u679c\u7684\u306b\u6d3b\u7528\u3059\u308b\u305f\u3081\u306b\u306f\u3001\u9069\u5207\u306a\u8a2d\u5b9a\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306e\u7406\u89e3\u304c\u4e0d\u53ef\u6b20\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u5b9f\u8df5\u7684\u306a\u30e2\u30c7\u30eb\u8a2d\u5b9a\u306e\u65b9\u6cd5\u3068\u3001\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u30fb\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-8\">\u30e2\u30c7\u30eb\u30af\u30e9\u30b9\u306e\u4f5c\u6210\u3068\u30b9\u30ad\u30fc\u30de\u5b9a\u7fa9\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-9\">1. \u30e2\u30c7\u30eb\u751f\u6210\u3068\u30de\u30a4\u30b0\u30ec\u30fc\u30b7\u30e7\u30f3<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u30e2\u30c7\u30eb\u306e\u751f\u6210\n# rails generate model User name:string email:string:uniq age:integer status:string\n# \u4e0a\u8a18\u30b3\u30de\u30f3\u30c9\u3067\u4ee5\u4e0b\u306e\u30d5\u30a1\u30a4\u30eb\u304c\u751f\u6210\u3055\u308c\u307e\u3059\n\n# db\/migrate\/YYYYMMDDHHMMSS_create_users.rb\nclass CreateUsers &lt; ActiveRecord::Migration[7.0]\n  def change\n    create_table :users do |t|\n      t.string :name, null: false  # NOT NULL\u5236\u7d04\n      t.string :email, null: false # NOT NULL\u5236\u7d04\n      t.integer :age\n      t.string :status, default: 'active'  # \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u8a2d\u5b9a\n\n      # created_at, updated_at\u30ab\u30e9\u30e0\u306e\u8ffd\u52a0\n      t.timestamps\n    end\n\n    # \u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u8ffd\u52a0\n    add_index :users, :email, unique: true  # \u30e6\u30cb\u30fc\u30af\u5236\u7d04\u4ed8\u304d\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n    add_index :users, [:status, :created_at]  # \u8907\u5408\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-10\">2. \u30e2\u30c7\u30eb\u306e\u8a2d\u5b9a\u3068\u30b9\u30b3\u30fc\u30d7\u5b9a\u7fa9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># app\/models\/user.rb\nclass User &lt; ApplicationRecord\n  # \u5b9a\u6570\u306e\u5b9a\u7fa9\n  VALID_STATUSES = ['active', 'inactive', 'pending']\n\n  # \u30c7\u30d5\u30a9\u30eb\u30c8\u30b9\u30b3\u30fc\u30d7\u306e\u8a2d\u5b9a\n  default_scope { order(created_at: :desc) }\n\n  # \u540d\u524d\u4ed8\u304d\u30b9\u30b3\u30fc\u30d7\u306e\u5b9a\u7fa9\n  scope :active, -&gt; { where(status: 'active') }\n  scope :adults, -&gt; { where('age &gt;= ?', 20) }\n  scope :created_last_week, -&gt; { where(created_at: 1.week.ago..Time.current) }\n\n  # \u4eee\u60f3\u5c5e\u6027\u306e\u5b9a\u7fa9\n  attr_accessor :password\n\n  # \u30af\u30e9\u30b9\u30e1\u30bd\u30c3\u30c9\u306e\u5b9a\u7fa9\n  def self.find_by_credentials(email, password)\n    user = find_by(email: email)\n    user if user&amp;.authenticate(password)\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-11\">3. \u95a2\u9023\u4ed8\u3051\u306e\u5b9a\u7fa9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># app\/models\/user.rb\nclass User &lt; ApplicationRecord\n  # 1\u5bfe\u591a\u306e\u95a2\u9023\u4ed8\u3051\n  has_many :posts, dependent: :destroy\n  has_many :comments, through: :posts\n\n  # 1\u5bfe1\u306e\u95a2\u9023\u4ed8\u3051\n  has_one :profile, dependent: :destroy\n  has_one :setting\n\n  # \u591a\u5bfe\u591a\u306e\u95a2\u9023\u4ed8\u3051\n  has_and_belongs_to_many :groups\n\n  # \u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u95a2\u9023\u4ed8\u3051\n  has_many :images, as: :imageable\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-12\">\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3068\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-13\">1. \u57fa\u672c\u7684\u306a\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u8a2d\u5b9a<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class User &lt; ApplicationRecord\n  # \u5b58\u5728\u30c1\u30a7\u30c3\u30af\n  validates :name, :email, presence: true\n\n  # \u9577\u3055\u306e\u5236\u9650\n  validates :name, length: { minimum: 2, maximum: 50 }\n\n  # \u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u30c1\u30a7\u30c3\u30af\n  validates :email, format: { with: URI::MailTo::EMAIL_REGEXP }\n\n  # \u4e00\u610f\u6027\u30c1\u30a7\u30c3\u30af\n  validates :email, uniqueness: { case_sensitive: false }\n\n  # \u30ab\u30b9\u30bf\u30e0\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n  validate :age_must_be_valid\n\n  private\n\n  def age_must_be_valid\n    if age.present? &amp;&amp; (age &lt; 0 || age &gt; 150)\n      errors.add(:age, \"must be between 0 and 150\")\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-14\">2. \u6761\u4ef6\u4ed8\u304d\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Post &lt; ApplicationRecord\n  # \u7279\u5b9a\u306e\u6761\u4ef6\u4e0b\u3067\u306e\u307f\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n  validates :title, presence: true, if: :published?\n  validates :slug, uniqueness: true, unless: :draft?\n\n  # Proc\u3092\u4f7f\u7528\u3057\u305f\u6761\u4ef6\u6307\u5b9a\n  validates :category, presence: true,\n    if: -&gt; { published? &amp;&amp; !draft? }\n\n  # \u30ab\u30b9\u30bf\u30e0\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u305f\u6761\u4ef6\u6307\u5b9a\n  validates :content, length: { minimum: 1000 },\n    if: :long_form_article?\n\n  private\n\n  def long_form_article?\n    category == 'long_form'\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-15\">3. \u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u52b9\u679c\u7684\u306a\u5229\u7528<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class User &lt; ApplicationRecord\n  # \u4fdd\u5b58\u524d\u306e\u51e6\u7406\n  before_save :normalize_email\n  before_create :generate_token\n\n  # \u4fdd\u5b58\u5f8c\u306e\u51e6\u7406\n  after_create :send_welcome_email\n  after_save :clear_cache\n\n  # \u524a\u9664\u6642\u306e\u51e6\u7406\n  before_destroy :can_be_deleted?\n  after_destroy :cleanup_associated_data\n\n  private\n\n  def normalize_email\n    self.email = email.downcase.strip if email.present?\n  end\n\n  def generate_token\n    self.token = SecureRandom.hex(20) while User.exists?(token: token)\n  end\n\n  def send_welcome_email\n    UserMailer.welcome(self).deliver_later\n  end\n\n  def clear_cache\n    Rails.cache.delete(\"user\/#{id}\")\n  end\n\n  def can_be_deleted?\n    throw(:abort) if admin? &amp;&amp; User.admin.count == 1\n  end\n\n  def cleanup_associated_data\n    # \u95a2\u9023\u3059\u308b\u4e00\u6642\u30c7\u30fc\u30bf\u306e\u524a\u9664\u306a\u3069\n    TempFile.where(user_id: id).destroy_all\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-16\">\u5b9f\u88c5\u4e0a\u306e\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306e\u9806\u5e8f<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u57fa\u672c\u7684\u306a\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\uff08presence, format\u306a\u3069\uff09\u3092\u5148\u306b<\/li>\n\n\n\n<li>\u30ab\u30b9\u30bf\u30e0\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306f\u5f8c\u306b\u914d\u7f6e<\/li>\n\n\n\n<li>\u4f9d\u5b58\u95a2\u4fc2\u306e\u3042\u308b\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306e\u9806\u5e8f\u306b\u6ce8\u610f<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u4f7f\u7528\u6307\u91dd<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30e2\u30c7\u30eb\u306e\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u306b\u76f4\u63a5\u95a2\u4fc2\u3059\u308b\u51e6\u7406\u306e\u307f\u3092\u542b\u3081\u308b<\/li>\n\n\n\n<li>\u91cd\u3044\u51e6\u7406\u306f\u975e\u540c\u671f\u30b8\u30e7\u30d6\u306b\u59d4\u8b72\uff08Active Job\u4f7f\u7528\uff09<\/li>\n\n\n\n<li>\u526f\u4f5c\u7528\u306e\u5c11\u306a\u3044\u8a2d\u8a08\u3092\u5fc3\u304c\u3051\u308b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30b9\u30b3\u30fc\u30d7\u306e\u547d\u540d\u898f\u5247<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u691c\u7d22\u6761\u4ef6\u3092\u660e\u78ba\u306b\u8868\u3059\u540d\u524d\u3092\u3064\u3051\u308b<\/li>\n\n\n\n<li>\u8907\u6570\u5f62\u3092\u4f7f\u7528\uff08active_users\u306a\u3069\uff09<\/li>\n\n\n\n<li>\u524d\u7f6e\u8a5e\u3092\u9069\u5207\u306b\u4f7f\u7528\uff08created_before\u306a\u3069\uff09<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u8a2d\u5b9a\u3068\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u3092\u7406\u89e3\u3057\u3001\u9069\u5207\u306b\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u4fdd\u5b88\u6027\u304c\u9ad8\u304f\u3001\u5805\u7262\u306aRails\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u57fa\u672c\u3092\u8e0f\u307e\u3048\u305f\u4e0a\u3067\u3001\u3088\u308a\u9ad8\u5ea6\u306a\u30c7\u30fc\u30bf\u64cd\u4f5c\u624b\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-17\">ActiveRecord\u3067\u5b9f\u73fe\u3059\u308b\u9ad8\u5ea6\u306a\u30c7\u30fc\u30bf\u64cd\u4f5c<\/h2>\n\n\n\n<p>ActiveRecord\u3092\u4f7f\u3044\u3053\u306a\u3059\u305f\u3081\u306b\u306f\u3001\u8907\u96d1\u306a\u691c\u7d22\u6761\u4ef6\u306e\u69cb\u7bc9\u65b9\u6cd5\u3084\u3001\u30e2\u30c7\u30eb\u9593\u306e\u95a2\u9023\u6027\u3092\u52b9\u679c\u7684\u306b\u7ba1\u7406\u3059\u308b\u65b9\u6cd5\u3092\u7406\u89e3\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u5b9f\u8df5\u7684\u306a\u9ad8\u5ea6\u30c7\u30fc\u30bf\u64cd\u4f5c\u30c6\u30af\u30cb\u30c3\u30af\u3092\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-18\">\u8907\u96d1\u306a\u6761\u4ef6\u3067\u306e\u30ec\u30b3\u30fc\u30c9\u691c\u7d22\u3068\u7d5e\u308a\u8fbc\u307f\u624b\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-19\">1. \u9ad8\u5ea6\u306a\u691c\u7d22\u6761\u4ef6\u306e\u69cb\u7bc9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class User &lt; ApplicationRecord\n  # \u8907\u6570\u306e\u6761\u4ef6\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u691c\u7d22\n  scope :search_by_criteria, -&gt;(criteria) {\n    queries = []\n    values = {}\n\n    if criteria[:keyword].present?\n      queries &lt;&lt; \"(name LIKE :keyword OR email LIKE :keyword)\"\n      values[:keyword] = \"%#{criteria[:keyword]}%\"\n    end\n\n    if criteria[:status].present?\n      queries &lt;&lt; \"status = :status\"\n      values[:status] = criteria[:status]\n    end\n\n    if criteria[:age_from].present?\n      queries &lt;&lt; \"age &gt;= :age_from\"\n      values[:age_from] = criteria[:age_from]\n    end\n\n    if criteria[:age_to].present?\n      queries &lt;&lt; \"age &lt;= :age_to\"\n      values[:age_to] = criteria[:age_to]\n    end\n\n    where(queries.join(' AND '), values)\n  }\nend\n\n# \u4f7f\u7528\u4f8b\nUser.search_by_criteria(\n  keyword: \"yamada\",\n  status: \"active\",\n  age_from: 20,\n  age_to: 30\n)<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-20\">2. \u30b5\u30d6\u30af\u30a8\u30ea\u306e\u6d3b\u7528<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u6295\u7a3f\u6570\u306e\u591a\u3044\u30e6\u30fc\u30b6\u30fc\u3092\u53d6\u5f97\nclass User &lt; ApplicationRecord\n  scope :active_posters, -&gt; {\n    joins(\"LEFT JOIN posts ON posts.user_id = users.id\")\n      .group(\"users.id\")\n      .having(\"COUNT(posts.id) &gt; ?\", 5)\n  }\n\n  # \u6700\u65b0\u306e\u6295\u7a3f\u304c\u3042\u308b\u65e5\u4ed8\u7bc4\u56f2\u306e\u30e6\u30fc\u30b6\u30fc\u3092\u53d6\u5f97\n  scope :recent_posters, -&gt;(days) {\n    where(id: Post.where('created_at &gt; ?', days.days.ago)\n                 .select(:user_id)\n                 .distinct)\n  }\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-21\">3. \u52d5\u7684\u306a\u691c\u7d22\u6761\u4ef6<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ProductsController &lt; ApplicationController\n  def index\n    @products = Product.all\n\n    # \u52d5\u7684\u306b\u691c\u7d22\u6761\u4ef6\u3092\u8ffd\u52a0\n    filtering_params.each do |key, value|\n      @products = @products.public_send(key, value) if value.present?\n    end\n\n    @products = @products.order(created_at: :desc)\n  end\n\n  private\n\n  def filtering_params\n    params.slice(:price_range, :category, :brand, :availability)\n  end\nend\n\nclass Product &lt; ApplicationRecord\n  scope :price_range, -&gt;(range) {\n    min, max = range.split('-').map(&amp;:to_i)\n    where(price: min..max)\n  }\n\n  scope :category, -&gt;(category) { where(category: category) }\n  scope :brand, -&gt;(brand) { where(brand: brand) }\n  scope :availability, -&gt;(status) { where(in_stock: status) }\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-22\">\u30a2\u30bd\u30b7\u30a8\u30fc\u30b7\u30e7\u30f3\u3092\u6d3b\u7528\u3057\u305f\u30e2\u30c7\u30eb\u9593\u306e\u95a2\u4fc2\u6027\u7ba1\u7406<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-23\">1. \u9ad8\u5ea6\u306a\u95a2\u9023\u4ed8\u3051\u306e\u5b9a\u7fa9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Order &lt; ApplicationRecord\n  belongs_to :user\n  has_many :order_items\n  has_many :products, through: :order_items\n\n  # \u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u95a2\u9023\u4ed8\u3051\n  has_many :notifications, as: :notifiable\n\n  # \u95a2\u9023\u4ed8\u3051\u306e\u30b9\u30b3\u30fc\u30d7\n  has_many :pending_items, -&gt; { where(status: 'pending') },\n           class_name: 'OrderItem'\n\n  # \u6761\u4ef6\u4ed8\u304d\u95a2\u9023\u4ed8\u3051\n  has_one :latest_payment, -&gt; { order(created_at: :desc) },\n          class_name: 'Payment'\n\n  # \u81ea\u5df1\u53c2\u7167\u95a2\u9023\u4ed8\u3051\n  belongs_to :parent_order, class_name: 'Order', optional: true\n  has_many :child_orders, class_name: 'Order',\n           foreign_key: 'parent_order_id'\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-24\">2. \u95a2\u9023\u30c7\u30fc\u30bf\u306e\u4e00\u62ec\u51e6\u7406<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Post &lt; ApplicationRecord\n  has_many :comments\n  has_many :tags\n\n  # \u30cd\u30b9\u30c8\u3055\u308c\u305f\u5c5e\u6027\u306e\u4e00\u62ec\u51e6\u7406\n  accepts_nested_attributes_for :comments,\n    reject_if: :all_blank,\n    allow_destroy: true\n\n  # \u30ab\u30b9\u30bf\u30e0\u30e1\u30bd\u30c3\u30c9\u3067\u306e\u4e00\u62ec\u51e6\u7406\n  def update_tags(tag_names)\n    transaction do\n      tags.destroy_all\n      tag_names.each do |name|\n        tags.create!(name: name)\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-25\">3. \u95a2\u9023\u30c7\u30fc\u30bf\u306e\u52b9\u7387\u7684\u306a\u8aad\u307f\u8fbc\u307f<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class BlogPost &lt; ApplicationRecord\n  has_many :comments\n  has_many :likes\n  belongs_to :author, class_name: 'User'\n  has_many :categorizations\n  has_many :categories, through: :categorizations\n\n  # \u95a2\u9023\u30c7\u30fc\u30bf\u3092\u542b\u3080\u30b9\u30b3\u30fc\u30d7\n  scope :with_summary, -&gt; {\n    select('blog_posts.*',\n           'COUNT(DISTINCT comments.id) as comments_count',\n           'COUNT(DISTINCT likes.id) as likes_count')\n      .left_joins(:comments, :likes)\n      .group('blog_posts.id')\n  }\n\n  # \u30d7\u30ea\u30ed\u30fc\u30c9\u7528\u30b9\u30b3\u30fc\u30d7\n  scope :with_associations, -&gt; {\n    includes(:author, :categories)\n      .preload(:comments)\n      .eager_load(:likes)\n  }\nend\n\n# \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u3067\u306e\u4f7f\u7528\u4f8b\nclass BlogPostsController &lt; ApplicationController\n  def index\n    @posts = BlogPost.with_associations\n                    .with_summary\n                    .page(params[:page])\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-26\">\u5b9f\u88c5\u4e0a\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u95a2\u9023\u4ed8\u3051\u306e\u9078\u629e\u57fa\u6e96<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>has_many through: \u4e2d\u9593\u30c6\u30fc\u30d6\u30eb\u306b\u8ffd\u52a0\u60c5\u5831\u304c\u5fc5\u8981\u306a\u5834\u5408<\/li>\n\n\n\n<li>has_and_belongs_to_many: \u30b7\u30f3\u30d7\u30eb\u306a\u591a\u5bfe\u591a\u306e\u95a2\u4fc2\u306e\u5834\u5408<\/li>\n\n\n\n<li>\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u95a2\u9023: \u540c\u3058\u95a2\u9023\u3092\u8907\u6570\u306e\u30e2\u30c7\u30eb\u3067\u5171\u6709\u3059\u308b\u5834\u5408<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c7\u30fc\u30bf\u8aad\u307f\u8fbc\u307f\u306e\u6700\u9069\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>includes: \u95a2\u9023\u30c7\u30fc\u30bf\u3092\u30d7\u30ea\u30ed\u30fc\u30c9\uff081+1\u30af\u30a8\u30ea\u306e\u9632\u6b62\uff09<\/li>\n\n\n\n<li>preload: \u5225\u500b\u306e\u30af\u30a8\u30ea\u3067\u95a2\u9023\u30c7\u30fc\u30bf\u3092\u8aad\u307f\u8fbc\u307f<\/li>\n\n\n\n<li>eager_load: LEFT OUTER JOIN\u3067\u4e00\u5ea6\u306b\u8aad\u307f\u8fbc\u307f<\/li>\n\n\n\n<li>joins: \u5185\u90e8\u7d50\u5408\u3067\u5fc5\u8981\u306a\u30c7\u30fc\u30bf\u306e\u307f\u8aad\u307f\u8fbc\u307f<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u914d\u616e<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5fc5\u8981\u306a\u95a2\u9023\u30c7\u30fc\u30bf\u306e\u307f\u3092\u30ed\u30fc\u30c9<\/li>\n\n\n\n<li>\u5927\u91cf\u30c7\u30fc\u30bf\u306e\u5834\u5408\u306f\u30d0\u30c3\u30c1\u51e6\u7406\u3092\u691c\u8a0e<\/li>\n\n\n\n<li>\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u9069\u5207\u306a\u8a2d\u5b9a<\/li>\n\n\n\n<li>N+1\u554f\u984c\u306e\u56de\u907f<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u9ad8\u5ea6\u306a\u30c7\u30fc\u30bf\u64cd\u4f5c\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u8907\u96d1\u306a\u30d3\u30b8\u30cd\u30b9\u30ed\u30b8\u30c3\u30af\u3092\u52b9\u7387\u7684\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u64cd\u4f5c\u3092\u3088\u308a\u52b9\u7387\u7684\u306b\u884c\u3046\u305f\u3081\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-27\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3057\u305fActiveRecord\u306e\u4f7f\u3044\u65b9<\/h2>\n\n\n\n<p>ActiveRecord\u306e\u4fbf\u5229\u306a\u6a5f\u80fd\u3092\u4f7f\u3044\u306a\u304c\u3089\u3082\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\u3059\u308b\u3053\u3068\u306f\u91cd\u8981\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u4e00\u822c\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u554f\u984c\u3068\u305d\u306e\u89e3\u6c7a\u65b9\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-28\">N+1\u554f\u984c\u306e\u7406\u89e3\u3068\u52b9\u7387\u7684\u306a\u89e3\u6c7a\u65b9\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-29\">1. N+1\u554f\u984c\u3068\u306f<\/h4>\n\n\n\n<p>N+1\u554f\u984c\u306f\u3001\u95a2\u9023\u4ed8\u3051\u3089\u308c\u305f\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3059\u308b\u969b\u306b\u767a\u751f\u3059\u308b\u4ee3\u8868\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u554f\u984c\u3067\u3059\u3002<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># N+1\u554f\u984c\u306e\u4f8b\nusers = User.all\nusers.each do |user|\n  puts user.posts.count  # \u5404\u30e6\u30fc\u30b6\u30fc\u3054\u3068\u306bSQL\u304c\u5b9f\u884c\u3055\u308c\u308b\nend\n\n# ActiveRecord\u306e\u30ed\u30b0\n# SELECT \"users\".* FROM \"users\"\n# SELECT COUNT(*) FROM \"posts\" WHERE \"posts\".\"user_id\" = 1\n# SELECT COUNT(*) FROM \"posts\" WHERE \"posts\".\"user_id\" = 2\n# SELECT COUNT(*) FROM \"posts\" WHERE \"posts\".\"user_id\" = 3\n# ...<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-30\">2. includes\u3001preload\u3001eager_load\u306e\u9069\u5207\u306a\u4f7f\u3044\u5206\u3051<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class PostsController &lt; ApplicationController\n  # includes\u306e\u4f7f\u7528\u4f8b\uff08\u95a2\u9023\u30c7\u30fc\u30bf\u3092\u5225\u30af\u30a8\u30ea\u3067\u53d6\u5f97\uff09\n  def index\n    @posts = Post.includes(:author, :comments)\n      .where(status: 'published')\n\n    # \u751f\u6210\u3055\u308c\u308bSQL:\n    # SELECT \"posts\".* FROM \"posts\" WHERE \"posts\".\"status\" = 'published'\n    # SELECT \"users\".* FROM \"users\" WHERE \"users\".\"id\" IN (1, 2, 3, ...)\n    # SELECT \"comments\".* FROM \"comments\" WHERE \"comments\".\"post_id\" IN (1, 2, 3, ...)\n  end\n\n  # eager_load\u306e\u4f7f\u7528\u4f8b\uff08LEFT JOIN\u3067\u4e00\u5ea6\u306b\u53d6\u5f97\uff09\n  def show\n    @post = Post.eager_load(:author, :categories)\n      .find(params[:id])\n\n    # \u751f\u6210\u3055\u308c\u308bSQL:\n    # SELECT \"posts\".*, \"users\".*, \"categories\".*\n    # FROM \"posts\"\n    # LEFT OUTER JOIN \"users\" ON \"users\".\"id\" = \"posts\".\"author_id\"\n    # LEFT OUTER JOIN \"categories\" ON \"categories\".\"post_id\" = \"posts\".\"id\"\n    # WHERE \"posts\".\"id\" = ?\n  end\n\n  # preload\u306e\u4f7f\u7528\u4f8b\uff08\u95a2\u9023\u30c7\u30fc\u30bf\u3092\u500b\u5225\u306b\u53d6\u5f97\uff09\n  def archived\n    @posts = Post.preload(:comments)\n      .where('created_at &lt; ?', 1.month.ago)\n\n    # \u751f\u6210\u3055\u308c\u308bSQL:\n    # SELECT \"posts\".* FROM \"posts\" WHERE created_at &lt; '2024-01-02'\n    # SELECT \"comments\".* FROM \"comments\" WHERE \"comments\".\"post_id\" IN (1, 2, 3, ...)\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-31\">\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3068\u30af\u30a8\u30ea\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-32\">1. \u52b9\u679c\u7684\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u8a2d\u8a08<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u30de\u30a4\u30b0\u30ec\u30fc\u30b7\u30e7\u30f3\u3067\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u8a2d\u5b9a\nclass AddIndexesToPosts &lt; ActiveRecord::Migration[7.0]\n  def change\n    # \u5358\u4e00\u30ab\u30e9\u30e0\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\n    add_index :posts, :title\n\n    # \u8907\u5408\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\uff08\u691c\u7d22\u9806\u5e8f\u3092\u8003\u616e\uff09\n    add_index :posts, [:status, :created_at]\n\n    # \u30e6\u30cb\u30fc\u30af\u5236\u7d04\u4ed8\u304d\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: \"published_at IS NOT NULL\"\n  end\nend\n\n# \u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\u3057\u305f\u30af\u30a8\u30ea\nclass Post &lt; ApplicationRecord\n  # status, created_at\u306e\u8907\u5408\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\n  scope :recent_active, -&gt; {\n    where(status: 'active')\n      .order(created_at: :desc)\n  }\n\n  # slug\u306e\u30e6\u30cb\u30fc\u30af\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u6d3b\u7528\n  scope :find_by_slug, -&gt;(slug) {\n    find_by!(slug: slug)\n  }\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-33\">2. \u30af\u30a8\u30ea\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Post &lt; ApplicationRecord\n  # \u9078\u629e\u3059\u308b\u30ab\u30e9\u30e0\u3092\u5236\u9650\n  scope :list_view, -&gt; {\n    select(:id, :title, :created_at)\n  }\n\n  # \u7d50\u5408\u30c6\u30fc\u30d6\u30eb\u3067\u306e\u7d5e\u308a\u8fbc\u307f\u3092\u52b9\u7387\u5316\n  scope :with_recent_comments, -&gt; {\n    joins(:comments)\n      .where('comments.created_at &gt; ?', 1.week.ago)\n      .distinct\n  }\n\n  # \u30ab\u30a6\u30f3\u30c8\u30af\u30a8\u30ea\u306e\u6700\u9069\u5316\n  def self.comment_stats\n    left_joins(:comments)\n      .group('posts.id')\n      .select('posts.*, COUNT(comments.id) as comments_count')\n  end\n\n  # \u5927\u91cf\u30c7\u30fc\u30bf\u306e\u52b9\u7387\u7684\u306a\u51e6\u7406\n  def self.process_in_batches\n    find_each(batch_size: 1000) do |post|\n      post.process_something\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-34\">3. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6539\u5584\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ApplicationRecord &lt; ActiveRecord::Base\n  # \u5171\u901a\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u30e1\u30bd\u30c3\u30c9\n  def self.cached_find(id)\n    Rails.cache.fetch(\"#{table_name}\/#{id}\", expires_in: 1.hour) do\n      find(id)\n    end\n  end\n\n  # \u5927\u91cf\u30c7\u30fc\u30bf\u306e\u4e00\u62ec\u51e6\u7406\n  def self.bulk_update(ids, attributes)\n    where(id: ids).update_all(attributes)\n  end\nend\n\nclass Post &lt; ApplicationRecord\n  # \u30ab\u30a6\u30f3\u30bf\u30fc\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u5229\u7528\n  belongs_to :blog, counter_cache: true\n\n  # \u975e\u540c\u671f\u3067\u306e\u95a2\u9023\u30c7\u30fc\u30bf\u66f4\u65b0\n  after_commit :update_search_index_async, on: [:create, :update]\n\n  private\n\n  def update_search_index_async\n    UpdateSearchIndexJob.perform_later(self)\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-35\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6539\u5584\u306e\u305f\u3081\u306e\u30c1\u30a7\u30c3\u30af\u30ea\u30b9\u30c8<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u30ec\u30d9\u30eb<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9069\u5207\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u8a2d\u5b9a<\/li>\n\n\n\n<li>\u4e0d\u8981\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u524a\u9664<\/li>\n\n\n\n<li>\u30c6\u30fc\u30d6\u30eb\u8a2d\u8a08\u306e\u6700\u9069\u5316<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30af\u30a8\u30ea\u30ec\u30d9\u30eb<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>N+1\u554f\u984c\u306e\u89e3\u6d88<\/li>\n\n\n\n<li>\u5fc5\u8981\u306a\u30ab\u30e9\u30e0\u306e\u307f\u306e\u53d6\u5f97<\/li>\n\n\n\n<li>\u9069\u5207\u306a\u95a2\u9023\u30c7\u30fc\u30bf\u306e\u8aad\u307f\u8fbc\u307f\u65b9\u6cd5\u306e\u9078\u629e<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u30ec\u30d9\u30eb<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u6d3b\u7528<\/li>\n\n\n\n<li>\u30d0\u30c3\u30c1\u51e6\u7406\u306e\u5b9f\u88c5<\/li>\n\n\n\n<li>\u975e\u540c\u671f\u51e6\u7406\u306e\u6d3b\u7528<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u76e3\u8996\u3068\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b9\u30ed\u30fc\u30af\u30a8\u30ea\u30ed\u30b0\u306e\u76e3\u8996<\/li>\n\n\n\n<li>\u5b9f\u884c\u8a08\u753b\u306e\u78ba\u8a8d<\/li>\n\n\n\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30e1\u30c8\u30ea\u30af\u30b9\u306e\u53ce\u96c6<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001ActiveRecord\u3092\u4f7f\u7528\u3057\u306a\u304c\u3089\u3082\u9ad8\u901f\u3067\u52b9\u7387\u7684\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u77e5\u8b58\u3092\u6d3b\u304b\u3057\u305f\u5b9f\u8df5\u7684\u306a\u958b\u767a\u30c6\u30af\u30cb\u30c3\u30af\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-36\">ActiveRecord\u3092\u4f7f\u3063\u305f\u5b9f\u8df5\u7684\u306a\u958b\u767a\u30c6\u30af\u30cb\u30c3\u30af<\/h2>\n\n\n\n<p>\u5b9f\u969b\u306e\u958b\u767a\u73fe\u5834\u3067\u306f\u3001\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406\u3084\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u306e\u53d6\u308a\u6271\u3044\u306a\u3069\u3001\u8907\u96d1\u306a\u8981\u4ef6\u306b\u5bfe\u5fdc\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001ActiveRecord\u3092\u4f7f\u7528\u3057\u305f\u5b9f\u8df5\u7684\u306a\u958b\u767a\u30c6\u30af\u30cb\u30c3\u30af\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-37\">\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-38\">1. \u57fa\u672c\u7684\u306a\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u51e6\u7406<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class OrderProcessor\n  def self.create_order(user, items)\n    ActiveRecord::Base.transaction do\n      # \u6ce8\u6587\u306e\u4f5c\u6210\n      order = Order.create!(user: user, status: 'pending')\n\n      # \u6ce8\u6587\u9805\u76ee\u306e\u4f5c\u6210\n      items.each do |item|\n        OrderItem.create!(\n          order: order,\n          product_id: item[:product_id],\n          quantity: item[:quantity]\n        )\n\n        # \u5728\u5eab\u306e\u66f4\u65b0\n        product = Product.lock.find(item[:product_id])\n        product.update!(stock: product.stock - item[:quantity])\n      end\n\n      # \u652f\u6255\u3044\u51e6\u7406\n      Payment.create!(order: order, amount: order.total_amount)\n\n      order\n    end\n  rescue ActiveRecord::RecordInvalid =&gt; e\n    # \u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u30a8\u30e9\u30fc\u306e\u51e6\u7406\n    Rails.logger.error \"Order creation failed: #{e.message}\"\n    raise OrderCreationError, \"\u6ce8\u6587\u306e\u4f5c\u6210\u306b\u5931\u6557\u3057\u307e\u3057\u305f\"\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-39\">2. \u30cd\u30b9\u30c8\u3055\u308c\u305f\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class AccountManager\n  def self.transfer_funds(from_account, to_account, amount)\n    Account.transaction do\n      # \u9001\u91d1\u5143\u306e\u30ed\u30c3\u30af\n      from_account.lock!\n\n      begin\n        Account.transaction(requires_new: true) do\n          # \u9001\u91d1\u5148\u306e\u30ed\u30c3\u30af\n          to_account.lock!\n\n          # \u6b8b\u9ad8\u30c1\u30a7\u30c3\u30af\n          raise InsufficientFundsError if from_account.balance &lt; amount\n\n          # \u9001\u91d1\u51e6\u7406\n          from_account.update!(balance: from_account.balance - amount)\n          to_account.update!(balance: to_account.balance + amount)\n\n          # \u53d6\u5f15\u5c65\u6b74\u306e\u4f5c\u6210\n          Transaction.create!(\n            from_account: from_account,\n            to_account: to_account,\n            amount: amount\n          )\n        end\n      rescue InsufficientFundsError\n        # \u5185\u90e8\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u30ed\u30fc\u30eb\u30d0\u30c3\u30af\n        raise\n      rescue =&gt; e\n        # \u305d\u306e\u4ed6\u306e\u30a8\u30e9\u30fc\u51e6\u7406\n        Rails.logger.error \"Transfer failed: #{e.message}\"\n        raise TransferError, \"\u9001\u91d1\u51e6\u7406\u306b\u5931\u6557\u3057\u307e\u3057\u305f\"\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-40\">3. \u6761\u4ef6\u4ed8\u304d\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class DocumentProcessor\n  def self.process_document(document, options = {})\n    # \u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u306e\u5fc5\u8981\u6027\u3092\u5224\u65ad\n    if options[:require_transaction]\n      process_with_transaction(document)\n    else\n      process_without_transaction(document)\n    end\n  end\n\n  private\n\n  def self.process_with_transaction(document)\n    Document.transaction do\n      yield_with_lock(document) do |doc|\n        process_content(doc)\n        update_status(doc)\n        notify_users(doc)\n      end\n    end\n  end\n\n  def self.yield_with_lock(record)\n    record.lock!\n    yield record\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-41\">\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u51e6\u7406\u306e\u52b9\u7387\u5316\u624b\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-42\">1. \u30d0\u30c3\u30c1\u51e6\u7406\u306e\u5b9f\u88c5<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class BatchProcessor\n  def self.process_users(batch_size: 1000)\n    # \u30d7\u30ed\u30b0\u30ec\u30b9\u8868\u793a\u306e\u6e96\u5099\n    total_count = User.count\n    processed_count = 0\n\n    User.find_each(batch_size: batch_size) do |user|\n      begin\n        process_user(user)\n        processed_count += 1\n\n        # \u9032\u6357\u72b6\u6cc1\u306e\u51fa\u529b\n        if (processed_count % batch_size).zero?\n          progress = (processed_count.to_f \/ total_count * 100).round(2)\n          Rails.logger.info \"Processed #{processed_count}\/#{total_count} users (#{progress}%)\"\n        end\n      rescue =&gt; e\n        # \u30a8\u30e9\u30fc\u30ed\u30b0\u306e\u8a18\u9332\n        Rails.logger.error \"Error processing user #{user.id}: #{e.message}\"\n        # \u30a8\u30e9\u30fc\u7ba1\u7406\u30b7\u30b9\u30c6\u30e0\u3078\u306e\u901a\u77e5\n        Bugsnag.notify(e)\n      end\n    end\n  end\n\n  private\n\n  def self.process_user(user)\n    ActiveRecord::Base.transaction do\n      user.update_statistics!\n      user.recalculate_scores!\n      user.refresh_cache!\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-43\">2. \u4e26\u884c\u51e6\u7406\u306e\u5b9f\u88c5<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ParallelProcessor\n  def self.process_data(records)\n    # \u4e26\u884c\u51e6\u7406\u306e\u8a2d\u5b9a\n    thread_count = Rails.env.production? ? 4 : 2\n    queue = Queue.new\n\n    # \u30c7\u30fc\u30bf\u3092\u30ad\u30e5\u30fc\u306b\u6295\u5165\n    records.each { |record| queue &lt;&lt; record }\n\n    # \u30b9\u30ec\u30c3\u30c9\u30d7\u30fc\u30eb\u306e\u4f5c\u6210\n    threads = thread_count.times.map do\n      Thread.new do\n        while record = queue.pop(true) rescue nil\n          process_record(record)\n        end\n      end\n    end\n\n    # \u3059\u3079\u3066\u306e\u30b9\u30ec\u30c3\u30c9\u306e\u5b8c\u4e86\u3092\u5f85\u6a5f\n    threads.each(&amp;:join)\n  end\n\n  private\n\n  def self.process_record(record)\n    ActiveRecord::Base.connection_pool.with_connection do\n      record.process_async_task\n    end\n  rescue =&gt; e\n    Rails.logger.error \"Processing failed for record #{record.id}: #{e.message}\"\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-44\">3. \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class MemoryOptimizer\n  def self.export_large_dataset\n    # \u30b9\u30c8\u30ea\u30fc\u30df\u30f3\u30b0\u51e6\u7406\u306e\u6e96\u5099\n    filename = \"export_#{Time.current.to_i}.csv\"\n\n    CSV.open(filename, 'wb', force_quotes: true) do |csv|\n      csv &lt;&lt; ['ID', 'Name', 'Email', 'Created At']\n\n      User.find_each do |user|\n        csv &lt;&lt; [\n          user.id,\n          user.name,\n          user.email,\n          user.created_at.to_s(:db)\n        ]\n\n        # \u30e1\u30e2\u30ea\u306e\u89e3\u653e\u3092\u4fc3\u9032\n        ActiveRecord::Base.connection.clear_query_cache\n        GC.start if (User.current_row % 10000).zero?\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-45\">\u5b9f\u88c5\u6642\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c8\u30e9\u30f3\u30b6\u30af\u30b7\u30e7\u30f3\u7ba1\u7406<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9069\u5207\u306a\u30ed\u30c3\u30af\u6226\u7565\u306e\u9078\u629e<\/li>\n\n\n\n<li>\u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u306e\u9632\u6b62<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u5fb9\u5e95<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u51e6\u7406<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u76e3\u8996<\/li>\n\n\n\n<li>\u9069\u5207\u306a\u30d0\u30c3\u30c1\u30b5\u30a4\u30ba\u306e\u9078\u629e<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u3068\u30ea\u30c8\u30e9\u30a4\u51e6\u7406<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b3\u30cd\u30af\u30b7\u30e7\u30f3\u30d7\u30fc\u30eb\u306e\u9069\u5207\u306a\u8a2d\u5b9a<\/li>\n\n\n\n<li>GC\u306e\u5236\u5fa1<\/li>\n\n\n\n<li>\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u52b9\u679c\u7684\u306a\u5229\u7528<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u5b9f\u8df5\u7684\u306a\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u5805\u7262\u3067\u52b9\u7387\u7684\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u5b9f\u88c5\u3092\u30c6\u30b9\u30c8\u3059\u308b\u65b9\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-46\">ActiveRecord\u306e\u30c6\u30b9\u30c8\u99c6\u52d5\u958b\u767a<\/h2>\n\n\n\n<p>ActiveRecord\u30e2\u30c7\u30eb\u306e\u4fe1\u983c\u6027\u3092\u78ba\u4fdd\u3059\u308b\u305f\u3081\u306b\u306f\u3001\u9069\u5207\u306a\u30c6\u30b9\u30c8\u306e\u5b9f\u88c5\u304c\u4e0d\u53ef\u6b20\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u52b9\u679c\u7684\u306a\u30c6\u30b9\u30c8\u624b\u6cd5\u3068\u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u4f5c\u6210\u65b9\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-47\">\u30e2\u30c7\u30eb\u306e\u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u4f5c\u6210\u624b\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-48\">1. RSpec\u3092\u4f7f\u7528\u3057\u305f\u30e2\u30c7\u30eb\u30b9\u30da\u30c3\u30af<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># spec\/models\/user_spec.rb\nrequire 'rails_helper'\n\nRSpec.describe User, type: :model do\n  # \u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306e\u30c6\u30b9\u30c8\n  describe 'validations' do\n    it { should validate_presence_of(:email) }\n    it { should validate_uniqueness_of(:email).case_insensitive }\n    it { should validate_presence_of(:name) }\n    it { should validate_length_of(:password).is_at_least(8) }\n  end\n\n  # \u30a2\u30bd\u30b7\u30a8\u30fc\u30b7\u30e7\u30f3\u306e\u30c6\u30b9\u30c8\n  describe 'associations' do\n    it { should have_many(:posts).dependent(:destroy) }\n    it { should have_one(:profile).dependent(:destroy) }\n    it { should belong_to(:organization).optional }\n  end\n\n  # \u30b9\u30b3\u30fc\u30d7\u306e\u30c6\u30b9\u30c8\n  describe 'scopes' do\n    let!(:active_user) { create(:user, status: 'active') }\n    let!(:inactive_user) { create(:user, status: 'inactive') }\n\n    describe '.active' do\n      it 'returns only active users' do\n        expect(User.active).to include(active_user)\n        expect(User.active).not_to include(inactive_user)\n      end\n    end\n  end\n\n  # \u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u30e1\u30bd\u30c3\u30c9\u306e\u30c6\u30b9\u30c8\n  describe '#full_name' do\n    let(:user) { build(:user, first_name: 'John', last_name: 'Doe') }\n\n    it 'returns the full name' do\n      expect(user.full_name).to eq('John Doe')\n    end\n  end\n\n  # \u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u30c6\u30b9\u30c8\n  describe 'callbacks' do\n    describe 'before_save' do\n      it 'normalizes email address' do\n        user = build(:user, email: ' User@Example.Com ')\n        user.save\n        expect(user.email).to eq('user@example.com')\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-49\">2. \u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3092\u8003\u616e\u3057\u305f\u30c6\u30b9\u30c8\u8a2d\u8a08<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># spec\/models\/order_spec.rb\nRSpec.describe Order, type: :model do\n  describe '#calculate_total' do\n    context '\u901a\u5e38\u306e\u5546\u54c1\u306e\u307f\u306e\u5834\u5408' do\n      let(:order) { create(:order) }\n      let!(:order_items) {\n        create_list(:order_item, 3, order: order, price: 1000)\n      }\n\n      it '\u5408\u8a08\u91d1\u984d\u304c\u6b63\u3057\u304f\u8a08\u7b97\u3055\u308c\u308b' do\n        expect(order.calculate_total).to eq(3000)\n      end\n    end\n\n    context '\u5272\u5f15\u5bfe\u8c61\u5546\u54c1\u3092\u542b\u3080\u5834\u5408' do\n      let(:order) { create(:order) }\n      let!(:regular_item) {\n        create(:order_item, order: order, price: 1000)\n      }\n      let!(:discounted_item) {\n        create(:order_item, order: order, price: 1000, discount: 0.2)\n      }\n\n      it '\u5272\u5f15\u3092\u8003\u616e\u3057\u305f\u5408\u8a08\u91d1\u984d\u304c\u8a08\u7b97\u3055\u308c\u308b' do\n        expect(order.calculate_total).to eq(1800)\n      end\n    end\n\n    context '\u7a0e\u7387\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u308b\u5834\u5408' do\n      let(:order) { create(:order, tax_rate: 0.1) }\n      let!(:order_items) {\n        create_list(:order_item, 2, order: order, price: 1000)\n      }\n\n      it '\u7a0e\u8fbc\u306e\u5408\u8a08\u91d1\u984d\u304c\u8a08\u7b97\u3055\u308c\u308b' do\n        expect(order.calculate_total).to eq(2200)\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-50\">\u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u4f5c\u6210\u3068\u30d5\u30a1\u30af\u30c8\u30ea\u306e\u6d3b\u7528\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-51\">1. Factory Bot\u3092\u4f7f\u7528\u3057\u305f\u30d5\u30a1\u30af\u30c8\u30ea\u306e\u5b9a\u7fa9<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># spec\/factories\/users.rb\nFactoryBot.define do\n  factory :user do\n    sequence(:email) { |n| \"user#{n}@example.com\" }\n    name { \"#{Faker::Name.first_name} #{Faker::Name.last_name}\" }\n    password { 'password123' }\n    status { 'active' }\n\n    # \u30c8\u30ec\u30a4\u30c8\u306e\u5b9a\u7fa9\n    trait :admin do\n      admin { true }\n      role { 'admin' }\n    end\n\n    trait :with_posts do\n      after(:create) do |user|\n        create_list(:post, 3, user: user)\n      end\n    end\n\n    trait :with_profile do\n      after(:create) do |user|\n        create(:profile, user: user)\n      end\n    end\n\n    # \u30cd\u30b9\u30c8\u3055\u308c\u305f\u30d5\u30a1\u30af\u30c8\u30ea\n    factory :admin_user do\n      admin { true }\n      role { 'admin' }\n    end\n\n    factory :premium_user do\n      status { 'premium' }\n      subscription_end_date { 1.year.from_now }\n    end\n  end\nend\n\n# spec\/factories\/posts.rb\nFactoryBot.define do\n  factory :post do\n    association :user\n    title { Faker::Lorem.sentence }\n    content { Faker::Lorem.paragraphs(number: 3).join(\"\\n\\n\") }\n    status { 'draft' }\n\n    trait :published do\n      status { 'published' }\n      published_at { Time.current }\n    end\n\n    trait :with_comments do\n      after(:create) do |post|\n        create_list(:comment, 3, post: post)\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-52\">2. \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u52b9\u7387\u7684\u306a\u751f\u6210<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># spec\/support\/test_data_helper.rb\nmodule TestDataHelper\n  def create_test_data\n    # \u57fa\u672c\u30c7\u30fc\u30bf\u306e\u4f5c\u6210\n    admin = create(:admin_user)\n    users = create_list(:user, 3, :with_profile)\n\n    # \u30e6\u30fc\u30b6\u30fc\u3054\u3068\u306e\u6295\u7a3f\u4f5c\u6210\n    users.each do |user|\n      create_list(:post, 2, :published, user: user)\n      create(:post, :with_comments, user: user)\n    end\n\n    # \u95a2\u9023\u30c7\u30fc\u30bf\u306e\u4f5c\u6210\n    create_list(:category, 5)\n\n    # \u623b\u308a\u5024\u3068\u3057\u3066\u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u3092\u8fd4\u3059\n    {\n      admin: admin,\n      users: users,\n      total_posts: Post.count,\n      total_comments: Comment.count\n    }\n  end\n\n  def cleanup_test_data\n    # \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\n    User.destroy_all\n    Post.destroy_all\n    Comment.destroy_all\n    Category.destroy_all\n  end\nend\n\n# spec\/rails_helper.rb\nRSpec.configure do |config|\n  config.include TestDataHelper\n\n  config.before(:suite) do\n    DatabaseCleaner.strategy = :transaction\n    DatabaseCleaner.clean_with(:truncation)\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-53\">\u30c6\u30b9\u30c8\u5b9f\u88c5\u306e\u91cd\u8981\u30dd\u30a4\u30f3\u30c8<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c6\u30b9\u30c8\u306e\u69cb\u9020\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9069\u5207\u306a describe\/context\/it \u306e\u968e\u5c64\u69cb\u9020<\/li>\n\n\n\n<li>\u30c6\u30b9\u30c8\u30b1\u30fc\u30b9\u306e\u660e\u78ba\u306a\u547d\u540d<\/li>\n\n\n\n<li>\u671f\u5f85\u3059\u308b\u7d50\u679c\u306e\u660e\u78ba\u306a\u8a18\u8ff0<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d5\u30a1\u30af\u30c8\u30ea\u306e\u8a2d\u8a08<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5fc5\u8981\u6700\u5c0f\u9650\u306e\u30c7\u30fc\u30bf\u5b9a\u7fa9<\/li>\n\n\n\n<li>\u30c8\u30ec\u30a4\u30c8\u3092\u6d3b\u7528\u3057\u305f\u67d4\u8edf\u306a\u62e1\u5f35<\/li>\n\n\n\n<li>\u95a2\u9023\u30c7\u30fc\u30bf\u306e\u9069\u5207\u306a\u751f\u6210<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c6\u30b9\u30c8\u306e\u4fdd\u5b88\u6027<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>DRY\u306a\u30c6\u30b9\u30c8\u30b3\u30fc\u30c9\u306e\u7dad\u6301<\/li>\n\n\n\n<li>\u5171\u901a\u51e6\u7406\u306e\u30d8\u30eb\u30d1\u30fc\u30e1\u30bd\u30c3\u30c9\u5316<\/li>\n\n\n\n<li>\u30c7\u30fc\u30bf\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\u306e\u78ba\u5b9f\u306a\u5b9f\u65bd<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30c6\u30b9\u30c8\u624b\u6cd5\u3092\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001ActiveRecord\u30e2\u30c7\u30eb\u306e\u54c1\u8cea\u3092\u78ba\u4fdd\u3057\u3001\u5b89\u5168\u306a\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u3084\u6a5f\u80fd\u8ffd\u52a0\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u5b9f\u904b\u7528\u6642\u306e\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-54\">ActiveRecord\u306e\u904b\u7528\u7ba1\u7406\u3068\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0<\/h2>\n\n\n\n<p>\u5b9f\u904b\u7528\u74b0\u5883\u3067\u306eActiveRecord\u306e\u7ba1\u7406\u306b\u306f\u3001\u69d8\u3005\u306a\u8ab2\u984c\u304c\u767a\u751f\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u4e00\u822c\u7684\u306a\u30a8\u30e9\u30fc\u30d1\u30bf\u30fc\u30f3\u3068\u305d\u306e\u89e3\u6c7a\u65b9\u6cd5\u3001\u52b9\u679c\u7684\u306a\u30c7\u30d0\u30c3\u30b0\u624b\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-55\">\u4e00\u822c\u7684\u306a\u30a8\u30e9\u30fc\u30d1\u30bf\u30fc\u30f3\u3068\u89e3\u6c7a\u65b9\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-56\">1. \u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u63a5\u7d9a\u306b\u95a2\u3059\u308b\u554f\u984c<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># config\/database.yml \u3067\u306e\u63a5\u7d9a\u8a2d\u5b9a\u306e\u6700\u9069\u5316\nproduction:\n  adapter: postgresql\n  host: &lt;%= ENV['DB_HOST'] %&gt;\n  database: &lt;%= ENV['DB_NAME'] %&gt;\n  username: &lt;%= ENV['DB_USER'] %&gt;\n  password: &lt;%= ENV['DB_PASSWORD'] %&gt;\n  pool: &lt;%= ENV.fetch(\"RAILS_MAX_THREADS\") { 5 } %&gt;\n  timeout: 5000\n  reconnect: true\n\n# \u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u63a5\u7d9a\u306e\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\nclass ApplicationRecord &lt; ActiveRecord::Base\n  def self.with_connection_monitoring\n    start_time = Time.current\n    yield\n  rescue ActiveRecord::ConnectionTimeoutError =&gt; e\n    Rails.logger.error \"[DB Connection] Timeout error: #{e.message}\"\n    Monitoring.notify_error(e)\n    raise\n  ensure\n    duration = Time.current - start_time\n    Rails.logger.info \"[DB Connection] Query took #{duration.round(2)}s\"\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-57\">2. N+1\u30af\u30a8\u30ea\u306e\u691c\u51fa\u3068\u4fee\u6b63<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># \u958b\u767a\u74b0\u5883\u3067\u306eN+1\u691c\u51fa\n# config\/environments\/development.rb\nconfig.after_initialize do\n  Bullet.enable = true\n  Bullet.rails_logger = true\n  Bullet.add_footer = true\nend\n\n# N+1\u554f\u984c\u306e\u4fee\u6b63\u4f8b\nclass PostsController &lt; ApplicationController\n  def index\n    # \u554f\u984c\u306e\u3042\u308b\u30b3\u30fc\u30c9\n    @posts = Post.all  # N+1\u304c\u767a\u751f\u3059\u308b\u53ef\u80fd\u6027\n\n    # \u4fee\u6b63\u5f8c\u306e\u30b3\u30fc\u30c9\n    @posts = Post.includes(:author, :comments)\n                .where(status: 'published')\n                .order(created_at: :desc)\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-58\">3. \u30c7\u30c3\u30c9\u30ed\u30c3\u30af\u306e\u51e6\u7406<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class OrderProcessor\n  def self.process_order(order)\n    retries = 0\n    begin\n      ActiveRecord::Base.transaction do\n        order.with_lock do\n          order.process_items\n          order.update_inventory\n          order.charge_payment\n        end\n      end\n    rescue ActiveRecord::Deadlocked =&gt; e\n      retries += 1\n      if retries &lt;= 3\n        Rails.logger.warn \"Deadlock detected, retry #{retries}\/3\"\n        sleep(rand(0.1..0.5))  # \u30e9\u30f3\u30c0\u30e0\u306a\u5f85\u6a5f\u6642\u9593\n        retry\n      else\n        Rails.logger.error \"Failed to process order after 3 retries\"\n        raise\n      end\n    end\n  end\nend<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-59\">\u30c7\u30d0\u30c3\u30b0\u3068\u30ed\u30b0\u89e3\u6790\u306e\u52b9\u679c\u7684\u306a\u65b9\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-60\">1. \u30ed\u30b0\u306e\u8a2d\u5b9a\u3068\u89e3\u6790<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># config\/environments\/production.rb\nconfig.logger = ActiveSupport::Logger.new(\"log\/#{Rails.env}.log\", 5, 100.megabytes)\n\n# \u30ab\u30b9\u30bf\u30e0\u30ed\u30b0\u30d5\u30a9\u30fc\u30de\u30c3\u30bf\u306e\u5b9f\u88c5\nclass CustomLogFormatter &lt; ActiveSupport::Logger::Formatter\n  def call(severity, timestamp, progname, msg)\n    {\n      timestamp: timestamp,\n      severity: severity,\n      message: msg,\n      pid: Process.pid,\n      thread_id: Thread.current.object_id,\n      environment: Rails.env\n    }.to_json + \"\\n\"\n  end\nend\n\n# \u30ed\u30b0\u306e\u89e3\u6790\u30d8\u30eb\u30d1\u30fc\nmodule LogAnalyzer\n  def self.analyze_slow_queries(log_file, threshold: 1.0)\n    slow_queries = []\n    File.foreach(log_file) do |line|\n      if line.include?('ActiveRecord::Base') &amp;&amp; \n         (duration = line[\/(\\d+\\.\\d+)ms\/, 1].to_f) &gt; threshold\n        slow_queries &lt;&lt; {\n          query: line,\n          duration: duration,\n          timestamp: line[\/\\[(.*?)\\]\/, 1]\n        }\n      end\n    end\n    slow_queries.sort_by { |q| -q[:duration] }\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-61\">2. \u30c7\u30d0\u30c3\u30b0\u30c4\u30fc\u30eb\u306e\u6d3b\u7528<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\"># development.rb \u3067\u306e\u30c7\u30d0\u30c3\u30b0\u8a2d\u5b9a\nclass Application &lt; Rails::Application\n  config.after_initialize do\n    # SQL \u30af\u30a8\u30ea\u306e\u30ed\u30b0\u51fa\u529b\u3092\u8a73\u7d30\u5316\n    ActiveRecord::Base.logger.level = Logger::DEBUG\n\n    # \u30af\u30a8\u30ea\u30bf\u30a4\u30df\u30f3\u30b0\u306e\u8a08\u6e2c\n    ActiveSupport::Notifications.subscribe('sql.active_record') do |*args|\n      event = ActiveSupport::Notifications::Event.new(*args)\n      if event.duration &gt; 100.0  # 100ms\u4ee5\u4e0a\u304b\u304b\u308b\u30af\u30a8\u30ea\u3092\u691c\u51fa\n        Rails.logger.warn \"Slow Query (#{event.duration.round(2)}ms): #{event.payload[:sql]}\"\n      end\n    end\n  end\nend\n\n# \u30c7\u30d0\u30c3\u30b0\u30d8\u30eb\u30d1\u30fc\u306e\u5b9f\u88c5\nmodule DebuggingHelper\n  def self.inspect_activerecord_object(record)\n    {\n      class: record.class.name,\n      attributes: record.attributes,\n      changed: record.changed?,\n      changes: record.changes,\n      errors: record.errors.full_messages,\n      associations: record.class.reflect_on_all_associations.map(&amp;:name),\n      validation_context: record.validation_context\n    }\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-62\">3. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">module ActiveRecordMonitoring\n  def self.track_query_statistics\n    stats = {\n      total_queries: 0,\n      slow_queries: 0,\n      query_types: Hash.new(0)\n    }\n\n    ActiveSupport::Notifications.subscribe('sql.active_record') do |*args|\n      event = ActiveSupport::Notifications::Event.new(*args)\n\n      stats[:total_queries] += 1\n      stats[:slow_queries] += 1 if event.duration &gt; 100.0\n\n      # \u30af\u30a8\u30ea\u30bf\u30a4\u30d7\u306e\u5206\u985e\n      query_type = event.payload[:sql].split.first.downcase\n      stats[:query_types][query_type] += 1\n\n      # \u30e1\u30c8\u30ea\u30af\u30b9\u306e\u9001\u4fe1\n      StatsD.gauge('activerecord.queries.total', stats[:total_queries])\n      StatsD.gauge('activerecord.queries.slow', stats[:slow_queries])\n    end\n  end\nend<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"i-63\">\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u554f\u984c\u306e\u7279\u5b9a\u3068\u5207\u308a\u5206\u3051<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u30ed\u30b0\u306e\u8a73\u7d30\u306a\u5206\u6790<\/li>\n\n\n\n<li>\u518d\u73fe\u624b\u9806\u306e\u660e\u78ba\u5316<\/li>\n\n\n\n<li>\u5f71\u97ff\u7bc4\u56f2\u306e\u7279\u5b9a<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u76e3\u8996<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b9\u30ed\u30fc\u30af\u30a8\u30ea\u306e\u5b9a\u671f\u7684\u306a\u30c1\u30a7\u30c3\u30af<\/li>\n\n\n\n<li>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u76e3\u8996<\/li>\n\n\n\n<li>\u30b3\u30cd\u30af\u30b7\u30e7\u30f3\u30d7\u30fc\u30eb\u306e\u72b6\u614b\u78ba\u8a8d<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4e88\u9632\u7684\u5bfe\u7b56<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5b9a\u671f\u7684\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u30e1\u30f3\u30c6\u30ca\u30f3\u30b9<\/li>\n\n\n\n<li>\u30af\u30a8\u30ea\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u9069\u5207\u306a\u8a2d\u5b9a<\/li>\n\n\n\n<li>\u30d0\u30c3\u30af\u30a2\u30c3\u30d7\u3068\u5fa9\u65e7\u624b\u9806\u306e\u6574\u5099<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u624b\u6cd5\u3068\u904b\u7528\u7ba1\u7406\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u7406\u89e3\u3057\u3001\u9069\u5207\u306b\u5b9f\u8df5\u3059\u308b\u3053\u3068\u3067\u3001ActiveRecord\u3092\u4f7f\u7528\u3057\u305f\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u5b89\u5b9a\u904b\u7528\u304c\u53ef\u80fd\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Warning: Undefined array key &#8220;is_admin&#8221; in \/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/ &#8230; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":{"0":"post-1219","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-ruby","7":"nothumb"},"_links":{"self":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1219","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1219"}],"version-history":[{"count":1,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1219\/revisions"}],"predecessor-version":[{"id":1220,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/1219\/revisions\/1220"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1219"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1219"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1219"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}