【RoR】PostgresのTableデータを丸ごと移行する方法

前提

• 前PCに Rails + PostgreSQL の DB がある
• 新PCに Rails 8.1 環境はインストール済み
• 新PCで rails db:create / rails db:migrate は済んでいる
• 移行したいのは データも含めた DB 全体

1️⃣ 前PCで DB をダンプ

ターミナルで以下を実行します

pg_dump -U <ユーザー名> -h localhost -F c -b -v -f myapp.dump <DB名>

• <ユーザー名>：Postgresユーザー名
• <DB名>：Railsプロジェクトの DB 名（config/database.yml の development/production）
• -F c：カスタム形式（復元が簡単）
• -b：バイナリデータも含める
• -v：詳細ログ出力

例

pg_dump -U postgres -h localhost -F c -b -v -f meetour.dump hpt8_development
Password: 
pg_dump: last built-in OID is 16383
pg_dump: reading extensions
pg_dump: identifying extension members
pg_dump: reading schemas
pg_dump: reading user-defined tables
pg_dump: reading user-defined functions
pg_dump: reading user-defined types
pg_dump: reading procedural languages
pg_dump: reading user-defined aggregate functions
pg_dump: reading user-defined operators
pg_dump: reading user-defined access methods
pg_dump: reading user-defined operator classes
pg_dump: reading user-defined operator families
pg_dump: reading user-defined text search parsers
pg_dump: reading user-defined text search templates
pg_dump: reading user-defined text search dictionaries
pg_dump: reading user-defined text search configurations
pg_dump: reading user-defined foreign-data wrappers
pg_dump: reading user-defined foreign servers
pg_dump: reading default privileges
pg_dump: reading user-defined collations
pg_dump: reading user-defined conversions
pg_dump: reading type casts
pg_dump: reading transforms
pg_dump: reading table inheritance information
pg_dump: reading event triggers
pg_dump: finding extension tables
pg_dump: finding inheritance relationships
pg_dump: reading column info for interesting tables
pg_dump: finding table default expressions
pg_dump: flagging inherited columns in subtables
pg_dump: reading partitioning data
pg_dump: reading indexes
pg_dump: flagging indexes in partitioned tables
pg_dump: reading extended statistics
pg_dump: reading constraints
pg_dump: reading triggers
pg_dump: reading rewrite rules
pg_dump: reading policies
pg_dump: reading row-level security policies
pg_dump: reading publications
pg_dump: reading publication membership of tables
pg_dump: reading publication membership of schemas
pg_dump: reading subscriptions
pg_dump: reading subscription membership of tables
pg_dump: reading large objects
pg_dump: reading dependency data
pg_dump: saving encoding = UTF8
pg_dump: saving "standard_conforming_strings = on"
pg_dump: saving "search_path = "
pg_dump: saving database definition
pg_dump: dumping contents of table "public.action_text_rich_texts"
pg_dump: dumping contents of table "public.active_storage_attachments"
pg_dump: dumping contents of table "public.active_storage_blobs"
pg_dump: dumping contents of table "public.active_storage_variant_records"
pg_dump: dumping contents of table "public.addresses"
pg_dump: dumping contents of table "public.ar_internal_metadata"
pg_dump: dumping contents of table "public.categories"
pg_dump: dumping contents of table "public.conversations"
pg_dump: dumping contents of table "public.event_orders"
pg_dump: dumping contents of table "public.event_pricings"
pg_dump: dumping contents of table "public.event_reviews"
pg_dump: dumping contents of table "public.events"
pg_dump: dumping contents of table "public.gigs"
pg_dump: dumping contents of table "public.local_government_taxes"
pg_dump: dumping contents of table "public.local_governments"
pg_dump: dumping contents of table "public.lodging_reviews"
pg_dump: dumping contents of table "public.messages"
pg_dump: dumping contents of table "public.notifications"
pg_dump: dumping contents of table "public.orders"
pg_dump: dumping contents of table "public.pricings"
pg_dump: dumping contents of table "public.reservations"
pg_dump: dumping contents of table "public.reviews"
pg_dump: dumping contents of table "public.roles"
pg_dump: dumping contents of table "public.room_availabilities"
pg_dump: dumping contents of table "public.rooms"
pg_dump: dumping contents of table "public.schema_migrations"
pg_dump: dumping contents of table "public.user_roles"
pg_dump: dumping contents of table "public.users"

2️⃣ ダンプファイルを新PCにコピー

USB、クラウド、ネットワークなどで myapp.dump を新PCに移動。

3️⃣ 新PCで DB を一度削除して作り直す

Rails で作った空DBにデータを追加する方法もあるが、外部キーやユニーク制約で失敗することが多いので DBを一度削除して復元するのが安全。

rails db:drop
rails db:create

これで完全に空の DB が作成されます

4️⃣ ダンプから復元

pg_restore -U <ユーザー名> -d <DB名> -v myapp.dump

例

pg_restore -U postgres -d hpt8_development -v meetour.dump

💡 まとめ

1. 前PCで pg_dump でダンプ
2. ダンプを新PCにコピー
3. 新PCで DB を削除 & 作成
4. pg_restore で復元
5. Rails コンソールでデータ確認

これだけで、Rails 8.1 + PostgreSQL の環境移行は安全に完了します。