Neo4j

Cypher

The SQL of Graphs. It uses ASCII-art patterns (node)-[RELATIONSHIP]->(node).

Index-Free Adjacency

In Neo4j, every node physically points to the next node. "Joins" are pre-computed pointers. Traversing 1 million relationships is O(1) per step, not O(Log N) like B-Trees.

Graph Data Science (GDS)

Library for algorithms like PageRank, Louvain (Community Detection), and Path Finding.

Best Practices (2025)

Do:

• Use GraphRAG: Combine Vector Search (Semantic) with Graph Traversal (Structural) for better AI answers.
• Model Relationships Richly: Put properties on relationships (e.g., [:REVIEWED {rating: 5, date: ...}]).
• Use Labels: Always label nodes (:Person) to optimize scans.

Don't:

• Don't create Supernodes: A node with 1 Million edges (e.g., (Justin Bieber)-[:FOLLOWED_BY]->(...)) hurts traversal performance.
• Don't use it for simple lookups: If you just need ByKey or Range, use a K-V store.

References

• Neo4j Documentation