Pdf - Neo4j In Action

“We need a faster way to follow relationships,” Alex said.

MATCH (tip:Tip)-[:MENTIONS]->(person:Person) WHERE tip.timestamp > datetime() - duration('PT5M') RETURN person.name, tip.text Within seconds of a new tip mentioning “Mr. X,” Alex’s dashboard lit up. With 2 million nodes and 5 million relationships, SQL queries took minutes. Neo4j used index-free adjacency —traversing relationships is O(1) per hop. The same queries ran in <50 ms. neo4j in action pdf

“It took 2 milliseconds,” Sam said. “And we didn’t even index anything yet.” Alex needed to know: how is Alice connected to a known criminal, Mr. X? “We need a faster way to follow relationships,”

CREATE (alice:Person name: 'Alice', age: 34) CREATE (bob:Person name: 'Bob', age: 29) CREATE (alice)-[:KNOWS]->(bob) A witness said: “Bob called a phone number, and that phone was used near the crime scene.” With 2 million nodes and 5 million relationships,

MATCH (p:Person name: 'Charlie')-[:VISITED|KNOWS]->(common)<-[:VISITED|KNOWS]-(other:Person) WHERE p <> other RETURN other.name, count(common) AS similarity ORDER BY similarity DESC This returned unknown associates—perfect for expanding investigations. The agency integrated Neo4j with Kafka. Every new tip became a new relationship. A trigger query ran every minute:

MATCH path = shortestPath( (alice:Person name: 'Alice')-[:KNOWS*..5]-(mrX:Person name: 'Mr. X') ) RETURN path The result: Alice → KNOWS → Bob → KNOWS → Dave → KNOWS → Mr. X

“Three hops,” Alex whispered. “We can now predict risk chains.” Using collaborative filtering , Sam wrote a query to find people similar to a suspect based on shared locations and contacts: