Innovate. Share. Connect.Boston June 10-11

What's new in Neo4j 2.0What's new in Neo4j 2.0Andreas Kollegger, Neo TechnologyAndreas Kollegger, Neo Technology

@akollegger@akollegger

Neo4j 2.0

★ 3 questions: Why? What? How?

★ with just One answer

Why 2.0?

Why 2.0?

• Neo4j 1.10 could be an AM radio station

• Wanted to seem web-savvy before it goes to 3.0

• We were in the mood to break some things

• Really, it's because of a shift in focus

(0.x) --> (1.x) --> (2.x)

• 0.x was about embedded java

• 1.x introduced the server and REST

• 2.x ease of use, big data, cloud

which means a focus on...

This guy

Focus on Cypher

• Cypher, a carefully crafted language for working with graphs

• Declarative, friendly, easy to read and write

• One language, used everywhere

• REST for management, Java for plugins,

What is new in 2.0?

There will be some sad Danes

"Once you label me,you negate me.”

- Søren Kierkegaard

• Simply: a label identifies a set of nodes

• Nodes can have multiple labels

• Find nodes by label

• Constrain properties and values

• (lightweight schema)

• A simple idea, with powerful applications

Introducing Node Labels

Find friends who like cheese

MATCH (max:People)-[:FRIENDS]->(cheesy: People), (cheesy)-[:LIKE]->(cheese:Things)

WHERE max.name = "Max De Marzi"

AND cheese.name = "Cheese"

RETURN cheesy;

Schema Indexing

• Indexes for labels, based on a property

• Simple lookups for now

• Unique indexing coming soon

• Full-text, other special indexes in planning

CREATE INDEX ON :People(name)

MERGE operation• a combination of MATCH + CREATE

• replaces CREATE UNIQUE

• attempts to MATCH, with specified properties and labels

• if match fails, new graph data is created

• optional sub-clauses for handling ON CREATE, and ON MATCH

MERGE (charlie { name:'Charlie Sheen', age:10 })RETURN charlie

• begin, commit, or rollback a transaction

• transaction as RESTful resource

• issue multiple statements per request

• multiple requests per transaction

• compact response format

Transactional Cypher

Anything else?

• Performance improvements

• Breaking changes to some APIs (read CHANGES.txt)

• Migration of "legacy" indexes (stop STARTing)

• Mandatory transactions for all DB interactions

• Improving installers (in progress)

• Changing everything to be "all Cypher, all the time"

How to use labels?

Label - to identify

name: Ford PrefectNINO: 122-762-9255HIKE: 415-484-6364

UKUKH2G2H2G2

Label - to identify

UKUKH2G2H2G2

MATCH (ford:H2G2) WHERE ford.HIKE = '415-484-6364' RETURN ford

Label - to avoid confusion

name: Ford Prefect name: Ford Prefect

AlienAlien CarCar

MATCH (ford:Alien) WHERE ford.name = 'Ford Prefect' RETURN ford

Label - special nodes

• replace built-in reference node, with domain specific reference nodes

4242AnswerAnswer

Labels - rules of thumb• Use a label to make queries easier to read & write

• And to improve performance through indexing

• Start with anything you might've put in a legacy index

• Use lightly, as few labels as needed

Is that it for 2.0?

Well, there is this...

What is new in 2.0?

• It's all about Cypher, starting with

• Labels, the first significant change in over 12 years

• Mix in schema indexing

• Then transactional REST, new clauses, functions

• A fresh Web UI that is Cypher-focused

Thanks :)

Any questions?

@akollegger to keep in touch