tags および tag_names にて論理削除を物理削除に変更 (#416) (#418)

Reviewed-on: #418
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/db/migrate/20260921020000_delete_discarded_records_from_tags.rb

@@ -0,0 +1,46 @@
+class DeleteDiscardedRecordsFromTags < ActiveRecord::Migration[8.0]
+  def up
+    remove_foreign_key :tag_versions, :tags, column: :tag_id
+    remove_foreign_key :nico_tag_versions, :tags, column: :tag_id
+    remove_foreign_key :material_versions, :tags, column: :tag_id
+
+    execute <<~SQL
+      DELETE
+        ntr
+      FROM
+        nico_tag_relations ntr
+        INNER JOIN
+          tags t
+          ON
+            t.discarded_at IS NOT NULL
+            AND t.id IN (ntr.tag_id, ntr.nico_tag_id)
+    SQL
+
+    execute <<~SQL
+      DELETE
+        ti
+      FROM
+        tag_implications ti
+        INNER JOIN
+          tags t
+          ON
+            t.discarded_at IS NOT NULL
+            AND t.id IN (ti.tag_id, ti.parent_tag_id)
+    SQL
+
+    execute <<~SQL
+      DELETE
+      FROM
+        tags
+      WHERE
+        discarded_at IS NOT NULL
+    SQL
+
+    remove_index :tags, :discarded_at
+    remove_column :tags, :discarded_at
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration, '戻せません．'
+  end
+end

backend/db/migrate/20260921030000_delete_discarded_records_from_tag_names.rb

@@ -0,0 +1,18 @@
+class DeleteDiscardedRecordsFromTagNames < ActiveRecord::Migration[8.0]
+  def up
+    execute <<~SQL
+      DELETE
+      FROM
+        tag_names
+      WHERE
+        discarded_at IS NOT NULL
+    SQL
+
+    remove_index :tag_names, :discarded_at
+    remove_column :tag_names, :discarded_at
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration, '戻せません．'
+  end
+end

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_09_21_010000) do
+ActiveRecord::Schema[8.0].define(version: 2026_09_21_030000) 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
@@ -409,9 +409,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_010000) do
     t.bigint "canonical_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.datetime "discarded_at"
     t.index ["canonical_id"], name: "index_tag_names_on_canonical_id"
-    t.index ["discarded_at"], name: "index_tag_names_on_discarded_at"
     t.index ["name"], name: "index_tag_names_on_name", unique: true
   end
 
@@ -448,10 +446,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_010000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "post_count", default: 0, null: false
-    t.datetime "discarded_at"
     t.integer "version_no", null: false
     t.index ["deprecated_at"], name: "index_tags_on_deprecated_at"
-    t.index ["discarded_at"], name: "index_tags_on_discarded_at"
     t.index ["tag_name_id"], name: "index_tags_on_tag_name_id", unique: true
     t.check_constraint "(`deprecated_at` is null) or (`category` <> _utf8mb4'nico')", name: "chk_tags_deprecated_at_not_nico"
     t.check_constraint "`version_no` > 0", name: "chk_tags_version_no_positive"
@@ -698,7 +694,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_010000) do
   add_foreign_key "material_sync_suppressions", "users", column: "created_by_user_id"
   add_foreign_key "material_versions", "materials"
   add_foreign_key "material_versions", "materials", column: "parent_id"
-  add_foreign_key "material_versions", "tags"
   add_foreign_key "material_versions", "users", column: "created_by_user_id"
   add_foreign_key "material_versions", "users", column: "updated_by_user_id"
   add_foreign_key "materials", "materials", column: "parent_id"
@@ -707,7 +702,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_010000) do
   add_foreign_key "materials", "users", column: "updated_by_user_id"
   add_foreign_key "nico_tag_relations", "tags"
   add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"
-  add_foreign_key "nico_tag_versions", "tags"
   add_foreign_key "nico_tag_versions", "users", column: "created_by_user_id"
   add_foreign_key "post_implications", "posts"
   add_foreign_key "post_implications", "posts", column: "parent_post_id"
@@ -726,7 +720,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_010000) do
   add_foreign_key "tag_names", "tag_names", column: "canonical_id"
   add_foreign_key "tag_similarities", "tags"
   add_foreign_key "tag_similarities", "tags", column: "target_tag_id"
-  add_foreign_key "tag_versions", "tags"
   add_foreign_key "tag_versions", "users", column: "created_by_user_id"
   add_foreign_key "tags", "tag_names"
   add_foreign_key "theatre_comments", "theatres"