graph databases - europython 2014

Graph DatabasesA little connected tour

Francisco Fernández Castaño

!

@fcofdezc

Beginning

The old town of Königsberg has seven bridges:

Can you take a walk through town, visiting each part of the town and crossing each bridge only once?

El origenG = (V, E)

What is a Graph DB?

Graph

Nodes Relationships

Properties

Stor

e Store

Connect

HaveHave

Written in Java

ACID

Rest interface

Cypher

Why Graph DB?

The traditional way in the context of connected data is artificial

!Scalability

Depth MySQL time (s) Neo4j time (s) Results

2 0.016 0.01 ~2500

3 30.267 0.168 ~110,000

4 1543.505 1.359 ~600,000

5 No Acaba 2.132 ~800,000

MySQL vs Neo4j

* Neo4J in Action

Person

Id Person

1 Frank

2 John

.. …

99 Alice

PersonFriend

PersonID FriendID

1 2

2 1

.. …

99 2

O(log n)

O(1)

O(m log n)

O(m)

We can transform our domain model in a natural way

Use cases

Social Networks

Follow

Follow

John Jeff

Douglas

Geospatial problems

Fraud detection

Authorization

Network management

Recommendation System

CypherDeclarative language

ASCII oriented

Pattern matching

CypherCypher

Traverser API

Core API

Kernel

Cypher

a b

(a)-->(b)

Cypher

clapton cream

(clapton)-[:play_in]->(cream)

play_in

Follow

FollowJohn Jeff

Douglas

Cypher

(john:User)-[:FOLLOW]->(jeff:User)!

(douglas:User)-[:FOLLOW]->(john:User)

Cypher

clapton {name: Eric Clapton}

cream

(clapton)-[:play_in]->(cream)<-[:labeled]-(blues)

play_in {date: 1968}

Blues

labeled

Cypher

MATCH (m)-[:PLAY_IN]—>(b)RETURN m,b;

Cypher

MATCH (m)-[:PLAY_IN]—>(b), (b)<-[:LABELED]-(s)RETURN m.name, t.date, s.name;

Cypher

MATCH (c {name: ‘clapton’})-[t:PLAY_IN]—>(b), (b)<-[:LABELED]-(s)RETURN c.name, b.name, s.name;

Cypher

MATCH (c {name: ‘clapton’})-[t:PLAY_IN]—>(b), (b)<-[:LABELED]-(e {name: ‘blues’})RETURN c.name, b.name, e.nameORDER BY t.date

Cypher

MATCH (c {name: ‘clapton’})-[r:PLAY_IN | PRODUCE]—>(b), (b)<-[:LABELED]-(e {name: ‘blues’})RETURN c.name, b.name, e.nameWHERE r.date > 1968ORDER BY r.date

Cypher

MATCH (a)-[:KNOW*5]—>(b)

MATCH p = (startNode:Station {name: ‘Sol’}) -[rels:CONNECTED_TO*]-> (endNode:Station {name: ‘Retiro’})RETURN p AS shortestPath, reduce(weight=0, r in rels: weight + r.weight) as tWeightORDER BY tWeight ASCLIMIT 1

Neo4J extensions

Managed

Unmanaged

Neo4J extensions

Managed

Unmanaged

Neo4J extensions

Managed

Unmanaged

Drivers/Clients

Instead of just picking a relational database because everyone does, we need to

understand the nature of the data we’re storing and how we want to manipulate it.

Martin Fowler

References

Neo4J as a service

http://www.graphenedb.com

Danke