From 48d3f7708e4f7e92ea920d440ad18db6fc9d95ba Mon Sep 17 00:00:00 2001
From: miteruzo <miteruzo@naver.com>
Date: Tue, 27 Jan 2026 01:02:33 +0900
Subject: [PATCH] #230

---
 backend/app/models/user_post_view.rb          |  2 +
 ..._change_user_post_views_to_composite_pk.rb | 47 +++++++++++++++++++
 backend/db/schema.rb                          |  5 +-
 3 files changed, 51 insertions(+), 3 deletions(-)
 create mode 100644 backend/db/migrate/20260127005300_change_user_post_views_to_composite_pk.rb

diff --git a/backend/app/models/user_post_view.rb b/backend/app/models/user_post_view.rb
index 2f6239f..ff604a7 100644
--- a/backend/app/models/user_post_view.rb
+++ b/backend/app/models/user_post_view.rb
@@ -1,4 +1,6 @@
 class UserPostView < ApplicationRecord
+  self.primary_key = :user_id, :post_id
+
   belongs_to :user
   belongs_to :post
 
diff --git a/backend/db/migrate/20260127005300_change_user_post_views_to_composite_pk.rb b/backend/db/migrate/20260127005300_change_user_post_views_to_composite_pk.rb
new file mode 100644
index 0000000..9f2d107
--- /dev/null
+++ b/backend/db/migrate/20260127005300_change_user_post_views_to_composite_pk.rb
@@ -0,0 +1,47 @@
+class ChangeUserPostViewsToCompositePk < ActiveRecord::Migration[8.0]
+  def up
+    execute <<~SQL
+      ALTER TABLE
+        user_post_views
+          MODIFY COLUMN id BIGINT NOT NULL
+      ;
+    SQL
+
+    execute <<~SQL
+      ALTER TABLE
+        user_post_views
+          DROP PRIMARY KEY
+      ;
+    SQL
+
+    remove_column :user_post_views, :id
+
+    execute <<~SQL
+      ALTER TABLE
+        user_post_views
+          ADD PRIMARY KEY (user_id, post_id)
+      ;
+    SQL
+
+    remove_index :user_post_views, name: 'index_user_post_views_on_user_id'
+  end
+
+  def down
+    execute <<~SQL
+      ALTER TABLE
+        user_post_views
+          DROP PRIMARY KEY
+      ;
+    SQL
+
+    execute <<~SQL
+      ALTER TABLE
+        user_post_views
+          ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT FIRST
+        , ADD PRIMARY KEY (id)
+      ;
+    SQL
+
+    add_index :user_post_views, :user_id, name: 'index_user_post_views_on_user_id'
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index 7ae8e2e..7a53c81 100644
--- a/backend/db/schema.rb
+++ b/backend/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_01_27_000900) do
+ActiveRecord::Schema[8.0].define(version: 2026_01_27_005300) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -152,13 +152,12 @@ ActiveRecord::Schema[8.0].define(version: 2026_01_27_000900) do
     t.index ["ip_address_id"], name: "index_user_ips_on_ip_address_id"
   end
 
-  create_table "user_post_views", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "user_post_views", primary_key: ["user_id", "post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.bigint "post_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["post_id"], name: "index_user_post_views_on_post_id"
-    t.index ["user_id"], name: "index_user_post_views_on_user_id"
   end
 
   create_table "users", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-- 
2.34.1