MongoDB vs PostgreSQL
2026年、最適なツールを選ぶための詳細比較
🏆 クイック判定
勝者: PostgreSQL
PostgreSQL is the better default choice for most applications due to its versatility, data integrity, and ability to handle both relational and JSON data. MongoDB is better for truly document-oriented workloads that need flexible schemas and horizontal scaling.
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📊 Visual Comparison
総合スコア比較
カテゴリー別分析
MongoDB ハイライト
- ✅ Flexible schema — no rigid table definitions required
- ✅ Horizontal scaling with built-in sharding
- 💰 Free / $57/month (dedicated)
PostgreSQL ハイライト
- ✅ Full ACID compliance with robust transactions
- ✅ Advanced SQL features (CTEs, window functions, etc.)
- 💰 Free (self-hosted)
機能比較
| Feature | MongoDB | PostgreSQL |
|---|---|---|
| Data Model | Document (JSON/BSON) | Relational + JSON (JSONB) |
| Schema | Flexible/Schemaless | Strict with migrations |
| ACID Transactions | Multi-document (since 4.0) | Full |
| Joins | $lookup (limited) | Full SQL joins |
| Scaling | Horizontal (sharding) | Vertical (read replicas for horizontal) |
| Replication | Replica sets | Streaming + logical |
| Full-text Search | Atlas Search | Built-in (tsvector) |
| Managed Cloud | MongoDB Atlas | Neon, Supabase, RDS, etc. |
| Drivers | 20+ languages | All major languages |
| Time-series | ✓ | Via TimescaleDB |
| Change Streams | ✓ | LISTEN/NOTIFY |
| Aggregation | Pipeline framework | SQL GROUP BY + window functions |
MongoDBとは？
MongoDB is the leading NoSQL document database. It stores data in flexible, JSON-like documents and is designed for scalability, high availability, and rapid development with schema-less data models.
✅メリット
- •Flexible schema — no rigid table definitions required
- •Horizontal scaling with built-in sharding
- •Excellent for rapid prototyping and agile development
- •Native JSON document storage
- •MongoDB Atlas offers a fully managed cloud service
- •Rich query language and aggregation pipeline
❌デメリット
- •No native joins (requires $lookup or denormalization)
- •ACID transactions are more limited than relational DBs
- •Can lead to data duplication without careful modeling
- •Higher storage overhead for structured data
- •Not ideal for complex relational data
PostgreSQLとは？
PostgreSQL is the world's most advanced open-source relational database. Known for its reliability, feature richness, and SQL compliance, it supports both relational and JSON data with strong ACID guarantees.
✅メリット
- •Full ACID compliance with robust transactions
- •Advanced SQL features (CTEs, window functions, etc.)
- •Supports both relational and JSON data (JSONB)
- •Excellent data integrity with constraints and types
- •Massive extension ecosystem (PostGIS, pgvector, etc.)
- •Completely free and open-source
❌デメリット
- •Vertical scaling primarily (horizontal is complex)
- •More rigid schema requirements
- •Can be slower for simple read-heavy workloads
- •Configuration tuning needed for optimal performance
- •Less intuitive for developers new to SQL
料金比較
MongoDB
Free / $57/month (dedicated)
Free tier (Atlas) / Self-hosted free
✓ 無料プランありView detailed pricing →📊詳細分析: MongoDB vs PostgreSQL
MongoDBとPostgreSQLのどちらを選ぶかは、両ツールが現代のワークフローに魅力的な機能を提供しているため、難しい選択となることがあります。この包括的な比較では、機能や価格から実際のユースケースまで、あらゆる側面を分析し、情報に基づいた意思決定をお手伝いします。
MongoDB
MongoDB is the leading NoSQL document database. It stores data in flexible, JSON-like documents and is designed for scalability, high availability, and rapid development with schema-less data models.
PostgreSQL
PostgreSQL is the world's most advanced open-source relational database. Known for its reliability, feature richness, and SQL compliance, it supports both relational and JSON data with strong ACID guarantees.
🎯最適なユースケース
MongoDBを選ぶべき時
- ✓チーム向け:
Flexible schema — no rigid table definitions required
- ✓中小企業向け:
Horizontal scaling with built-in sharding
- ✓エンタープライズ向け:
Excellent for rapid prototyping and agile development
PostgreSQLを選ぶべき時
- ✓個人向け:
Full ACID compliance with robust transactions
- ✓中小企業向け:
Advanced SQL features (CTEs, window functions, etc.)
- ✓チーム向け:
Supports both relational and JSON data (JSONB)
🔍機能の詳細分析
Data Model
Schema
ACID Transactions
Joins
Scaling
Replication
💰価格分析
MongoDB
Free tier (Atlas) / Self-hosted free
✅ 無料プランありPostgreSQL
Free and open-source
✅ 無料プランあり💡 Pro Tip
両ツールは無料トライアルまたは無料プランを提供しています。有料プランに加入する前に、実際のワークフローで両方をテストすることをお勧めします。
🏆おすすめ
広範な分析とテストの結果、私たちの見解は次のとおりです：MongoDBとPostgreSQLはどちらも生産性を大幅に向上させる優れたツールです。最適な選択は、あなたの具体的なニーズ、ワークフロー、優先事項によって異なります。
Choose MongoDB if:
You have truly unstructured data, need horizontal scaling, or are building real-time applications where schema flexibility is essential.
Choose PostgreSQL if:
You want robust data integrity, need complex queries and joins, or are building a typical web application where data relationships matter.
よくある質問
For simple document reads and writes, MongoDB can be faster. For complex queries involving joins and aggregations, PostgreSQL typically outperforms. Real-world performance depends heavily on data modeling and indexing.
最終結論：どちらを選ぶべき？
✨ MongoDBを選ぶべき場合
You have truly unstructured data, need horizontal scaling, or are building real-time applications where schema flexibility is essential.
✨ PostgreSQLを選ぶべき場合
You want robust data integrity, need complex queries and joins, or are building a typical web application where data relationships matter.