This document introduces graph databases and Neo4j. It discusses the key components of graphs including nodes, relationships, properties, and labels. It provides an example of using Cypher, Neo4j's query language, to find connected nodes and describes how to install and query a Neo4j database using sample queries. It also discusses building applications with Neo4j by using language drivers and outlines how Neo4j is used by customers.

1. Intro to Graphs

2. All the meetups

6. What’s a graph database?
Simply put, a graph consists of nodes connected by relationships.
Graph databases store data as graph structures (nodes and relationships)

7. Neo4j Fundamentals
• Nodes
• Relationships
• Properties
• Labels

8. CAR
Property Graph Model Components
Nodes
• Represent the objects in the graph
• Can be labeled
PERSON PERSON

9. CAR
DRIVES
Property Graph Model Components
Nodes
• Represent the objects in the graph
• Can be labeled
Relationships
• Relate nodes by type and direction
LOVES
LOVES
LIVES WITH
OW
NS
PERSON PERSON

10. CAR
DRIVES
name: “Dan”
born: May 29, 1970
twitter: “@dan”
name: “Ann”
born: Dec 5, 1975
since:
Jan 10, 2011
brand: “Volvo”
model: “V70”
Property Graph Model Components
Nodes
• Represent the objects in the graph
• Can be labeled
Relationships
• Relate nodes by type and direction
Properties
• Name-value pairs that can go on
nodes and relationships.
LOVES
LOVES
LIVES WITH
OW
NS
PERSON PERSON

11. Graphs are all around us
Can you identify nodes and relationships related to this meetup?

12. Summary of the graph building blocks
• Nodes - Entities and complex value types
• Relationships - Connect entities and structure domain
• Properties - Entity attributes, relationship qualities, metadata
• Labels - Group nodes by role

13. Cypher: Graph Query Language
MATCH (:Person { name:"Dan"} ) -[:LOVES]-> (:Person { name:"Ann"} )
LOVES
Dan Ann
LABEL PROPERTY
NODE NODE
LABEL PROPERTY

14. Let's get started
With ASCII ART ¯_(ツ)_/¯

15. Nodes
() or (n)
• Surrounded with parentheses
• Use an alias n to refer to our node later in the query

16. Nodes
() or (n)
• Surrounded with parentheses
• Use an alias n to refer to our node later in the query
(n:Label)
• Specify a Label, starting with a colon :
• Used to group nodes by roles or types (similar to tags)

17. Nodes
() or (n)
• Surrounded with parentheses
• Use an alias n to refer to our node later in the query
(n:Label)
• Specify a Label, starting with a colon :
• Used to group nodes by roles or types (similar to tags)
(n:Label {prop: 'value'})
• Nodes can have properties

18. --> or -[r:TYPE]->
• Wrapped with hyphens & square brackets
• A relationship type starts with a colon :
Relationships

19. --> or -[r:TYPE]->
• Wrapped with hyphens & square brackets
• A relationship type starts with a colon :
< > Specify the direction of the relationship
-[:KNOWS {since: 2010}]->
• Relationships can have properties too!
Relationships

20. • Used to query data
(n:Label {prop:'value'})-[:TYPE]->(m:Label)
Patterns

21. • Can you translate this pattern?
(p1:Person {name:'Alice'})-[:KNOWS]->(p2:Person {name:'Bob')
Patterns

22. • Find Alice who knows Bob
• In other words:
• find Person named 'Alice'
• who KNOWS
• a Person named 'Bob'
(p1:Person {name:'Alice'})-[:KNOWS]->(p2:Person {name:'Bob'})
Patterns

23. Demo

24. Navigate to neo4j.com/download
Installing Neo4j

25. Once you download,
For setup you will be asked to give a default location.
Click start! You are good to go.
Goto Browser type http://localhost:7474 Enter default password: neo4j
Instructions

26. Type :play movies into the query bar:
The movies graph

27. Type :play movies into the query bar:
The movies graph

28. Sample Queries to try out
// Find the Matrix
MATCH (movie:Movie {title:"The Matrix"})
RETURN movie
// Find the people who acted in any movie and return their name and
// the role they played in the movie
MATCH (actor:Person)-[rel:ACTED_IN]->(movie:Movie)
RETURN rel.roles, actor.name

29. Building an application

30. Language Drivers
Java
<dependency>
<groupId>org.neo4j.driver</groupId>
<artifactId>neo4j-java-driver</artifactId>
</dependency>
Python
pip install neo4j-driver
.NET
PM> Install-Package Neo4j.Driver
JavaScript
npm install neo4j-driver

31. Architecture and Data Flow
Application
Cypher Bolt Driver
Cypher Bolt Server
MATCH (a:Person)
WHERE a.name = 'Alice'
RETURN a.surname, a.age
{surname: 'Smith',
age: 33}
Parameterised
Cypher
Result
Stream
metadata

32. Driver -> Neo4j example
from neo4j.v1 import GraphDatabase, basic_auth
driver = GraphDatabase.driver("bolt://localhost", auth=basic_auth("neo4j", "neo4j"))
session = driver.session()
session.run("CREATE (a:Person {name:'Arthur', title:'King'})")
result = session.run("""MATCH (a:Person)
WHERE a.name = 'Arthur'
RETURN a.name AS name, a.title AS title""")
for record in result:
print("%s %s" % (record["title"], record["name"]))
session.close()

33. Who’s using Neo4j?

34. How Customers Use Neo4j
Network &
Data Center
Master Data
Management
Social Recommendations
Identity &
Access
Search &
Discovery
GEO

35. What next?

36. If you like meetups...
meetup.com/graphdb-london

37. If you like reading...
graphdatabases.com

38. If you like videos...
youtube.com/neo4j

39. If you like getting your hands dirty...
neo4j.com/online_training/graphdatabases

40. If you get stuck....
http://stackoverflow.com/tags/neo4j
http://neo4j.com/slack

41. In summary
• Flexible, iterative way of modeling data
• 4 building blocks - nodes, relationships, properties, labels
• Cypher Query Language - executable ASCII art
• Language drivers - Java, Javascript, .NET, Python