Webinar: What's new in Neo4j 2.0
-
Upload
neo4j-the-open-source-graph-database -
Category
Business
-
view
1.907 -
download
2
description
Transcript of Webinar: What's new in Neo4j 2.0
WebinarAug 8 2013
What‘s new in Neo4j 2.0Michael Hunger, Neo Technology
@mesirii | @neo4j
BIG NEWS
Neo4j 2.0.0-M04 released today!
Neo4j 2.0
Why 2.0?
(0.x) --> (1.x) --> (2.x)
• 0.x was about embedded java
• 1.x introduced indexes, 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 extensions
What is new in 2.0?
Introducing: Node Labels
WORKS_WITH
Person
Employee
Developer
Husband
NoSQL
GraphDB
Database
Awesome!
No Schema is goodSome Structure is helpful
• Simply: a label identifies a set of nodes
• Nodes can have multiple labels
• Find nodes by label
• Constrain properties and values
(lightweight, optional schema)
• A simple idea, with powerful applications
Introducing Node Labels
NoSQL
GraphDB
Database
Awesome!
How to use labels?
Labels - how to use?• To identify nodes
• To categorize, tag
• To represent types
• To avoid confusion
• For special nodes (domain specific reference nodes)
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
Find friends who like cheese
MATCH (p:Person)-[:FRIENDS]->(friend:Person),
(friend) -[:LIKE]-> (thing:Thing)
WHERE p.name = "Max De Marzi"
AND thing:Food AND thing.name = "Cheese"
RETURN thing, labels(thing);
Schema Indexing• Indexes for labels, based on a property
• Simple lookups for now
• Unique indexing coming soon
• Full-text, other special indexes in planningCREATE INDEX ON :Person(name)MATCH (p:Person)WHERE p.name = „Max“RETURN p
MERGE operation• a combination of MATCH + CREATE
• replaces CREATE UNIQUE (currently still limited)
• 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 MATCHMERGE (p:Person { name:'Charlie Sheen', age:10 })ON CREATE p SET p.created = timestamp()RETURN p
Hands-On Cypher
• Migrate Cineasts dataset to use Labels
• Show MATCH on Labels and Properties (+ profile)
• Add an Index on :Person(name) :Movie(title)
• Show MATCH on Labels and Properties (+ profile)
• Show MERGE with a user
https://gist.github.com/jexp/6193139#file-setup-start-shhttps://gist.github.com/jexp/6193139#file-upgrade-movie-database-to-2-0-cql
Demo
Anything else?
• 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"
Cypher Changes: Properties • no schema -> what happens when properties don‘t exist
• has(n.prop) AND n.prop=“Foobar“
• there was syntactic sugar n.prop! and n.prop?
• now n.prop returns NULL covers n.prop! =“Foobar“
• explicit expression for n.prop? = „Foobar“
WHERE n.name = „Chris“AND (not(m.name) OR m.name=“Andres“)
Cypher Changes: REMOVE • consistent remove operations of labels and properties
• you REMOVE attributes (properties, labels)
• and DELETE elements (nodes, relationships)
REMOVE n.nameREMOVE n:People
DELETE nodeDELETE relationship
Cypher Changes: Separators • grammar has to be unambiguous
• extract(n in nodes:Foo)???
• confuse colon from label and collection function separator
• exchanged colon for pipe
EXTRACT (n in nodes | n.name)FILTER (n in nodes | n.name =~ „And.*“)FOREACH (v in names | CREATE ( {name: v} ))
Demo
Mandatory Transactions• we had optional transactions for reads
• Issues:
• In which context do I read?
• Do I read what I read?
• Which changes do I see?
• NOW: Mandatory Transactions for reads and writes!
• only affects embedded API
• Cypher and REST-API take care of their transactions
• begin, commit, or rollback a transaction
• transaction as RESTful resource
• issue multiple statements per request
• multiple requests per transaction
• compact response format
• some driver already support it (neography, jdbc)
Transactional Cypher
Hands-On 2.0• Show Transactional HTTP-Endpoint
• POST initial statements, look at result, check currently running tx in server-info
• POST another create statement to the tx
• POST a new read statement to a new tx that shows isolation
• DELETE second transaction
• POST to COMMIT resourcehttps://gist.github.com/jexp/6193139#file-demo-transactional-endpoint-js
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 :)
MATCH (you)-[:HAVE]->(q:Question)RETURN q.text
@neo4j or @mesirii to keep in touch