Javaland Brühl March 2015

Intro to Neo4j JavaLand Brühl March 2015

Michael Hunger [email protected] @mesirii @neo4j

1. Why Graphs, Why Now? 2. What Is A Graph, Anyway? 3. Neo4j as a Graph Database 4. Graph Querying 1. Cypher 2. Examples

ACTED_IN ACTED_IN ACTED_IN

The Matrix Cloud Atlas DIRECTED

DIRECTED Lana Wachowski

name: Tom Hanks name: Hugo Weaving born: 1956 born: 1960

ACTED_IN ACTED_IN roles: Bill Smoke roles: Agent Smith ACTED_IN roles: Zachry

Movie

Movie title: The Matrix released: 1999 title: Cloud Atlas released: 2012

DIRECTED Person Director

DIRECTED name: Lana Wachowski born: 1965

Node

Relationship

Nodes can be connected by more than one relaonship

Nodes can have more than one relaonship

Self relaonships are allowed

(c) Neo Technology, Inc 2014 Four Building Blocks ๏ Nodes • Enes ๏ Relaonships • Connect enes and structure domain ๏ Properes • Aributes and metadata ๏ Labels • Group nodes by role

table1 join-table table2

actors actor_movie movies

๏a sample social graph • with ~1,000 persons ๏average 50 friends per person ๏pathExists(a,b) limited to depth 4 ๏caches warmed up to eliminate disk I/O

# persons query time

Relational database 1.000 2000ms

Neo4j 1.000 2ms

Neo4j 1.000.000 2ms

29 (c) Neo Technology, Inc 2014 Neo4j is a Graph Database

•Powerful data model, as general as RDBMS •Whiteboard friendly, agile development •Fast, for connected data •Easy to query

•Global Queries / Number Crunching •Binary Data / Blobs •Requires conceptual shift •graph-like thinking is addictive

select movie.title from actors join actor_movie on (...) join movies on (...) where actors.name = "Andreas"

actors actor_movie movies 36

// find starting points MATCH (:Person {name:'Andreas'}) // then traverse the relationships -[:ACTED_IN]->(movie:Movie) <-[:ACTED_IN]- (other:Person) // and return results RETURN other

Andreas

#1 Declarative You tell Cypher what you want, not how to get it

#2 Expressive Optimize syntax for reading

MATCH (p:Person)-[r:ACTED_IN]->(m:Movie) RETURN a.name, r.role, m.title

#3 Pattern Matching Patterns are easy for your human brain

(c) Neo Technology, Inc 2014 (c) Neo Technology, Inc 2014 MATCH (person:Person)-[:IS_FRIEND_OF]->(friend), (friend)-[:LIKES]->(restaurant), (restaurant)-[:LOCATED_IN]->(loc:Location), (restaurant)-[:SERVES]->(type:Cuisine)

WHERE person.name = 'Philip' AND loc.location='New York' AND type.cuisine='Sushi'

RETURN restaurant.name

http://maxdemarzi.com/?s=facebook (c) Neo Technology, Inc 2014 * Cypher query language example Query Structure

Find all Actors Whose name starts with "T" Aggregate their activity and movie titles Who acted in more than 5 movies Return their name, age and movie-titles Ordered by number of movies Limited to top 10

SELECT a.name, a.age, group_concat(m.title) as movies, count(*) as cnt FROM actors as a JOIN actor_movie ON (a.id = actor_movie.actor_id) JOIN movies as m ON (actor_movie.movie_id = m.id) WHERE a.name LIKE "T%" GROUP BY a.name, a.age HAVING cnt > 5

MATCH (a:Person)-[:ACTED_IN]->(m:Movie) WHERE a.name =~ "T.*" WITH a, count(m) AS cnt, collect(m.title) AS movies WHERE cnt > 5 RETURN a.name, a.age, movies ORDER BY length(movies) DESC LIMIT 10

GraphDatabaseService gdb = new GraphDatabaseFactory().newEmbeddedDatabase(PATH); try(Transaction tx = gdb.beginTx()) { Node actor = db.findNode("name","Tom Hanks") for (Relationship role : actor.getRelationships(ACTED_IN,OUTGOING)) { Node movie = role.getEndNode(); result.add(movie.getProperty("name")); } tx.success(); }

// Make sure Neo4j Driver is registered Class.forName("org.neo4j.jdbc.Driver");

// Connect Connection con = DriverManager.getConnection( "jdbc:neo4j://localhost:7474/");

// Query try(Statement stmt = con.createStatement()) { ResultSet rs = stmt.executeQuery( "MATCH (n:Person)-[:ACTED_IN]->… RETURN m.title");

while(rs.next()) { System.out.println(rs.getString("m.title")); } }

@NodeEntity class Person { @Indexed String name; @RelatedTo(type="ACTED_IN") Collection movies; } interface PersonRepository extends GraphRepository { Person findByName(String name); @Query("MATCH (:Person {name:{name}})-[:ACTED_IN]->…") Collection findColleagues(String name); } template.save(new Person("Tom Hanks"));

• you bring 10+ colleagues • you provide a room with a projector + screen • we bring a bag lunch • we introduce Neo4j to your team in 45 min + 15 min for Q&A http://neo4j.com/brownbag Schedule your Neo4j Intro now!

Neo Technology, Inc Conﬁdential Neo4j 2.0 Graph datenbank für alle

• Kompaktes Handbuch • Übersicht über Neo4j, APIs, Cypher • Praktische Anwendungsfälle und Beispiele • Genügend Details um direkt starten zu können

http://bit.ly/das-buch Buch-PDF gratis verfügbar.

Neo Technology, Inc Conﬁdential How to get started? ๏ Full day Neo4j Training & Online Training ๏ Free e-Books • Graph Databases, Neo4j 2.0 (DE) ๏ neo4j.com • neo4j.com/developer ๏ docs.neo4j.org • Data Modeling Examples ๏ http://console.neo4j.org ๏ http://graphgist.neo4j.com ๏ Get Neo4j • http://neo4j.com/download ๏ Participate • http://groups.google.com/group/neo4j http://neo4j.meetup.com • 78