Graph Databases

Purpose

This skill guides selection and implementation of graph databases for applications where relationships between entities are first-class citizens. Unlike relational databases that model relationships through foreign keys and joins, graph databases natively represent connections as properties, enabling efficient traversal-heavy queries.

When to Use This Skill

Use graph databases when:

• Deep relationship traversals (4+ hops): "Friends of friends of friends"
• Variable/evolving relationships: Schema changes don't break existing queries
• Path finding: Shortest route, network analysis, dependency chains
• Pattern matching: Fraud detection, recommendation engines, access control

Do NOT use graph databases when:

• Fixed schema with shallow joins (2-3 tables) → Use PostgreSQL
• Primarily aggregations/analytics → Use columnar databases
• Key-value lookups only → Use Redis/DynamoDB