The Football Graph - Neo4j and the Premier League

In a League of their Own: Neo4j and Premiership Football

Mark Needham @markhneedham

Outline

•  Intro to graphs •  When do we need a graph? •  Property graph model •  Neo4j’s query language •  The football graph •  Using Neo4j from .NET

Let’s talk graphs

You mean these?

EaJng Brains

Dancing With Michael Jackson

Nope!

EaJng Brains

Dancing With Michael Jackson Thes

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Ok so what’s a graph then?

Node

RelaJonship

The tube

The social network (graph)

Complexity

What are graphs good for?

complexity = f(size, semi-structure, connectedness)

Data Complexity


The Real Complexity

Semi-‐Structure

Email: [email protected] Email: [email protected] TwiXer: @markhneedham Skype: mk_jnr1984

USER

CONTACT

CONTACT_TYPE

FIRST_NAME LAST_NAME USER_ID EMAIL_1 EMAIL_2 TWITTER FACEBOOK SKYPE

Mark Needham 315 [email protected]

[email protected] @markhneedham NULL mk_jnr1984

Semi-‐Structure


The Real Complexity

Connectedness

When do we need a graph?

Densely Connected

Semi Structured

Densely connected?

Lots of join tables

Semi-‐Structured?

Lots of sparse tables

ProperJes of graph databases

• Millions of ‘joins’ per second •  Consistent query Jmes as dataset grows •  Join Complexity and Performance •  Easy to evolve data model •  Easy to ‘layer’ different types of data together

Property Graph Data Model

Nodes can have properJes

•  Used to represent enJty a"ributes and/or metadata (e.g. Jmestamps, version)

•  Key-‐value pairs •  Java primiJves •  Arrays •  null is not a valid value

•  Every node can have different properJes

What’s a node?

RelaJonships

RelaJonships

•  RelaJonships are first class ciJzens •  Every relaJonship has a name and a direc.on – Add structure to the graph – Provide semanJc context for nodes

•  ProperJes used to represent quality or weight of relaJonship, or metadata

•  Every relaJonship must have a start node and end node

RelaJonships

Nodes can have more than one relaJonship

Self relaJonships are allowed

Nodes can be connected by more than one relaJonship

Labels

Think Gmail labels

•  Nodes – EnJJes

•  RelaJonships – Connect enJJes and structure domain

•  ProperJes – EnJty aXributes, relaJonship qualiJes, and metadata

•  Labels – Group nodes by role

Four Building Blocks

Purposeful abstracJon of a domain designed to saJsfy parJcular applicaJon/end-‐user goals

Models

Model Query

Design for Queryability

Model Model


Model Query


Introducing Cypher

•  DeclaraJve PaXern-‐Matching language •  SQL-‐like syntax •  Designed for graphs

PaXerns, paXerns, everywhere

A

B C

(a) --> (b)

a b

It’s all about the ASCII art!

a b

The most basic query

MATCH (a)-->(b) RETURN a, b

(a)–[:ACTED_IN]->(m)

a m

Adding in a relaJonship type

ACTED IN

a m

Adding in a relaJonship type

MATCH (a)-[:ACTED_IN]->(m) RETURN a.name, m.name

ACTED IN

The football graph

Find Arsenal’s away matches


MATCH (team:Team)<-[:away_team]-(game)

WHERE team.name = "Arsenal"

RETURN game

Graph PaXern



RETURN game.name

Anchor paXern in graph



RETURN game.name

Create projecJon of results



RETURN game.name

Evolving the football graph

Find the top away goal scorers


MATCH (team)<-[:away_team]-(game:Game),

(game)<-[:contains_match]-(season:Season),

(team)<-[:for]-(stats)<-[:played]-(player),

(stats)-[:in]->(game)

WHERE season.name = "2012-2013"

RETURN player.name,

COLLECT(DISTINCT team.name),

SUM(stats.goals) as goals

ORDER BY goals DESC

LIMIT 10

MulJple graph paXerns






RETURN player.name,



ORDER BY goals DESC

LIMIT 10

Anchor paXern in the graph






RETURN player.name,



ORDER BY goals DESC

LIMIT 10

Group by player






RETURN player.name,



ORDER BY goals DESC

LIMIT 10

Other football queries

• Goals scored in each month by Michu •  ToXenham results when Gareth Bale scores • What did Wayne Rooney do in April? • Which players only score when a game is televised?

Graph Query Design

The relaJonal version

Graph vs RelaJonal

Rela%onal Graphs Tables -‐ assume records all have the same structure

Nodes -‐ no need to set a property if it doesn’t exist

Foreign keys between tables -‐ joins calculated at run Jme -‐ the more tables you join to a query the slower the query gets

Rela%onships -‐ stored as a ‘Pre-‐computed index’ at write Jme -‐ very easy to do lots of ‘hops’ between relaJonships

.NET and Neo4j

REST Client

ApplicaJon

H T T P

Neo4j Server

Neo4jClient

.NET and Neo4j

ApplicaJon

H T T P

Neo4j Server

REST Client

.NET and Neo4j

Thinking in graphs

Graphs should be fun!

Ask for help if you get stuck Last Wednesday of the month

Come take a copy, it’s free!

Ian Robinson, Jim Webber & Emil Eifrem

Graph Databases

h

Compliments

of Neo Technology

www.graphdatabases.com

QuesJons?

Mark Needham @markhneedham [email protected]

The Football Graph - Neo4j and the Premier League

Sports

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