Extensibility for Java Developers in Neo4j

Extensibility for Java Developers in Neo4j Jennifer Reif Neo4j @JMHReif

Software Engineer, Neo4j - Developer - Blogger - Conference speaker
- Continuous learner Hobbies: cats, coffee, and traveling :) [email protected] @JMHReif Who Am I?

What is a Graph Database?

Chart Graph

Database - specifically graph • Database: a structured set of
data held in a computer, especially one that is accessible in various ways. • Relational? NoSQL? Graph? • Graph database: uses graph structures for semantic queries with nodes, edges and properties to represent and store data.

Neo4j is a Graph Database

Neo4j Fast Reliable No size limit Binary & HTTP protocol
ACID transactions 2-4 M  ops/s per core Clustering scale & HA Official Drivers Neo4j is a database

Neo4j Native GraphDB Cypher Query Language Developer Workbench Extensible Procedures
& Functions Schema Free Property Graph Model Graph Visualization Graph Storage Neo4j is a graph database

Neo4j Developer Surface Native LanguageDrivers BOLT User- Defined Procedure 2000-2010
0.x Embedded Java API 2010-2014 1.x REST 2014-2015 2.x Cypher over HTTP 2016 3.0.x Bolt, Official Language Drivers, User-Defined Procedures 2016 3.1.x User-Defined Functions 2017 3.2.x User-Defined Aggregation Functions

0.x Embedded Java API 2010-2014 1.x REST 2014-2015 2.x Cypher over HTTP 2016 3.0.x Bolt, Official Language Drivers, User Defined Procedures 2016 3.1.x User Defined Functions 2017 3.2.x User Defined Aggregation Functions

Interfaces to Neo4j • BOLT: • binary protocol / Cypher-only
pipe • type system similar to Cypher • official drivers • HTTP: • familiar protocol • JSON (lossy) • community drivers / standard HTTP tooling • Embedded: • Java-only • core API • in-process

Bolt Binary Protocol • High-performance protocol • Secure transport (auth/TLS)
• Shared connections (pooling) • More inclusive data type system • Procedure functionality

Neo4j Bolt Drivers

Official Drivers

Java Driver import org.neo4j.driver.v1.*; Driver driver = GraphDatabase.driver( "bolt://localhost", AuthTokens.basic(
"neo4j", "neo4j" ) ); Session session = driver.session(); session.run( "CREATE (a:Person {name:'Arthur', title:'King'})" ); StatementResult result = session.run( "MATCH (a:Person) WHERE a.name = 'Arthur' RETURN a.name AS name, a.title AS title" ); while ( result.hasNext() ) { Record record = result.next(); System.out.println( record.get( "title" ).asString() + " " + record.get("name").asString() ); } session.close(); driver.close(); github.com/neo4j/neo4j-java-driver / org.neo4j.driver:neo4j-java-driver:1.5.0

Javascript Driver var neo4j = require('neo4j-driver').v1; var driver = neo4j.driver("bolt://localhost",
neo4j.auth.basic("neo4j", "neo4j")); var session = driver.session(); session .run( "CREATE (a:Person {name:'Arthur', title:'King'})" ) .then( function() { return session.run( "MATCH (a:Person) WHERE a.name = 'Arthur' RETURN a.name AS name, a.title AS title" ) }) .then( function( result ) { console.log( result.records[0].get("title") + " " + result.records[0].get("name") ); session.close(); driver.close(); }) github.com/neo4j/neo4j-javascript-driver / npm install neo4j-driver

Python Driver 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'})") query = "MATCH (a:Person) WHERE a.name = 'Arthur' RETURN a.name AS name, a.title AS title" result = session.run(query) for record in result: print("%s %s" % (record["title"], record["name"])) session.close() github.com/neo4j/neo4j-python-driver / pip install neo4j-driver

.NET Driver using Neo4j.Driver.V1; using (var driver = GraphDatabase.Driver("bolt://localhost", AuthTokens.Basic("neo4j",
"neo4j"))) using (var session = driver.Session()) { session.Run("CREATE (a:Person {name:'Arthur', title:'King'})"); var result = session.Run("MATCH (a:Person) WHERE a.name = 'Arthur' RETURN a.name AS name, a.title AS title"); foreach (var record in result) { Output.WriteLine($"{record["title"].As<string>()} {record["name"].As<string>()}"); } } github.com/neo4j/neo4j-dotnet-driver / PM> Install-Package Neo4j.Driver-1.0.3

Community Drivers

Spring Data Neo4j & Object-Graph Mapper

https://projects.spring.io/spring-data-neo4j/

https://github.com/spring-projects/spring-data-neo4j

Capabilities • Can use with SpringBoot • Annotation-based OGM for
POJOs • Connect to Neo4j with Bolt, HTTP, and embedded • Interface-based repository support • Persistence lifecycle events

@NodeEntity public class Person { @Id @GeneratedValue private Long id;
private String name; private int born; @Relationship(type = "ACTED_IN") private List<Movie> movies = new ArrayList<>(); } @NodeEntity public class Movie { … @JsonIgnoreProperties("movie") @Relationship(type = "ACTED_IN", direction = Relationship.INCOMING) private List<Role> roles; } @RelationshipEntity(type = "ACTED_IN") public class Role { @Id @GeneratedValue private Long id; private List<String> roles = new ArrayList<>(); @StartNode private Person person; @EndNode private Movie movie; }

public interface MovieRepository extends Neo4jRepository<Movie, Long> { //derived finder methods
- auto-mapping Movie findByTitle(@Param("title") String title); Collection<Movie> findByTitleLike(@Param("title") String title); @Query("MATCH (m:Movie)<-[r:ACTED_IN]-(a:Person) RETURN m,r,a LIMIT {limit}") Collection<Movie> graph(@Param("limit") int limit); }

@Service public class MovieService { private final MovieRepository movieRepository; public
MovieService(MovieRepository movieRepository) { this.movieRepository = movieRepository; } @Transactional(readOnly = true) public Movie findByTitle(String title) { return movieRepository.findByTitle(title); } @Transactional(readOnly = true) public Collection<Movie> findByTitleLike(String title) { return movieRepository.findByTitleLike(title); } @Transactional(readOnly = true) public Map<String, Object> graph(int limit) { Collection<Movie> result = movieRepository.graph(limit); return toD3Format(result); } } https://neo4j.com/developer/spring-data-neo4j/

0.x Embedded Java API 2010-2014 1.x REST 2014-2015 2.x Cypher over HTTP 2016 3.0.x Bolt, Official Language Drivers, User-Defined Procedures 2016 3.1.x User-Defined Functions 2017 3.2.x User-Defined Aggregation Functions

Procedures Functions Aggregate Functions

Can be written in any JVM language

User-Defined Procedures

Callable as Stand-Alone or in Cypher Statements

CALL example.search('User','name:Brook*')

public class FullTextIndex { @Context public GraphDatabaseService db; @Procedure( name
= "example.search", mode = Procedure.Mode.READ ) public Stream<SearchHit> search( @Name("index") String index,   @Name("query") String query ) { if( !db.index().existsForNodes( index )) { return Stream.empty(); } return db.index().forNodes( index ).query( query ).stream()  .map( SearchHit::new ); } public static class SearchHit { public final Node node; SearchHit(Node node) { this.node = node; } } }

try ( Driver driver = GraphDatabase.driver("bolt://localhost", Config.build().toConfig()) ) { try
( Session session = driver.session() ) { String call = "CALL example.search('User',$query)"; Map<String,Object> params = singletonMap("query", "name:Brook*"); StatementResult result = session.run(call, params); while ( result.hasNext() ) { // process results } } }

User-Defined Functions

Useable in any Cypher expression or lightweight computation

RETURN example.join(['Hello','World'],' ') => "Hello World"

public class Join { @UserFunction @Description("example.join(['s1','s2',...], delimiter) - join the
given strings with the given delimiter.") public String join( @Name(“strings") List<String> strings, @Name(value = "delimiter", defaultValue = ",") String delimiter) { if ( strings == null || delimiter == null ) { return null; } return String.join( delimiter, strings ); } }

public class Join { @UserFunction @Description("example.join(['s1','s2',...], delimiter) - join the
given strings with the given delimiter.") public String join( @Name("strings") List<String> strings, @Name(value = "delimiter", defaultValue = ",") String delimiter) { if ( strings == null || delimiter == null ) { return null; } return String.join( delimiter, strings ); } }

try ( Driver driver = GraphDatabase.driver( "bolt://localhost",   Config.build().toConfig() )
) { try ( Session session = driver.session() ) { String query = "RETURN example.join(['Hello','World']) AS result"; String result = session.run( query ) .single().get( "result" ).asString(); } }

User-Defined Aggregation Functions

Custom, efficient aggregations for Data Science and BI

UNWIND ['abc', 'abcd', 'ab'] AS string  RETURN example.longestString(string) => 'abcd'

public class LongestString { @UserAggregationFunction @Description( "aggregates the longest string
found" ) public LongStringAggregator longestString() { return new LongStringAggregator(); } public static class LongStringAggregator { private int longest; private String longestString; @UserAggregationUpdate public void findLongest( @Name( "string" ) String string ) { if ( string != null && string.length() > longest) { longest = string.length(); longestString = string; } } @UserAggregationResult public String result() { return longestString; } } }

try ( Driver driver = GraphDatabase.driver("bolt://localhost",   Config.build().toConfig()) ) {
try ( Session session = driver.session() ) { String query = "UNWIND ['abc', 'abcd', 'ab'] AS string " + "RETURN example.longestString(string) AS result"; String result = session.run(query).single().get("result").asString(); } }

Awesome Procedures On Cypher

450+ procedures and functions

APOC - Data Integration

Load from a relational database

apoc.load.jdbc WITH "jdbc:mysql://localhost:3306/northwind?user=root" AS url CALL apoc.load.jdbc(url,"products")   YIELD row
MERGE (p:Product {id: row.ProductID}) SET p.name = row.ProductName, p.unitPrice = row.UnitPrice

WITH "jdbc:mysql://localhost:3306/northwind?user=root" AS url CALL apoc.load.jdbc(url,"products")   YIELD row MERGE
(p:Product {id: row.ProductID}) SET p.name = row.ProductName, p.unitPrice = row.UnitPrice Execute procedure

Apply Cypher transformation WITH "jdbc:mysql://localhost:3306/northwind?user=root" AS url CALL apoc.load.jdbc(url,"products")  
YIELD row MERGE (p:Product {id: row.ProductID}) SET p.name = row.ProductName, p.unitPrice = row.UnitPrice

Load XML

apoc.load.xml CALL apoc.load.xml('http://overpass.osm.rambler.ru/cgi/xapi_meta *[bbox=11.54,48.14,11.543,48.145]') YIELD value UNWIND value["_children"] AS child
WITH child WHERE child["_type"] = "node" WITH child.id AS id,   child.lat AS latitude,   child.lon AS longitude,   child["user"] AS userName MERGE (point:Point {id: id}) SET point.latitude = latitude,   point.longitude = longitude MERGE (user:User {name: userName}) MERGE (user)-[:EDITED]->(point)

Execute procedure CALL apoc.load.xml('http://overpass.osm.rambler.ru/cgi/xapi_meta? *[bbox=11.54,48.14,11.543,48.145]') YIELD value UNWIND value["_children"] AS
child WITH child WHERE child["_type"] = "node" WITH child.id AS id,   child.lat AS latitude,   child.lon AS longitude,   child["user"] AS userName MERGE (point:Point {id: id}) SET point.latitude = latitude,   point.longitude = longitude MERGE (user:User {name: userName}) MERGE (user)-[:EDITED]->(point)

UNWIND the array of elements CALL apoc.load.xml('http://overpass.osm.rambler.ru/cgi/xapi_meta? *[bbox=11.54,48.14,11.543,48.145]') YIELD value
UNWIND value["_children"] AS child WITH child WHERE child["_type"] = "node" WITH child.id AS id,   child.lat AS latitude,   child.lon AS longitude,   child["user"] AS userName MERGE (point:Point {id: id}) SET point.latitude = latitude,   point.longitude = longitude MERGE (user:User {name: userName}) MERGE (user)-[:EDITED]->(point)

Filter rows CALL apoc.load.xml('http://overpass.osm.rambler.ru/cgi/xapi_meta? *[bbox=11.54,48.14,11.543,48.145]') YIELD value UNWIND value["_children"] AS
child WITH child WHERE child["_type"] = "node" WITH child.id AS id,   child.lat AS latitude,   child.lon AS longitude,   child["user"] AS userName MERGE (point:Point {id: id}) SET point.latitude = latitude,   point.longitude = longitude MERGE (user:User {name: userName}) MERGE (user)-[:EDITED]->(point)

Apply Cypher transformation CALL apoc.load.xml('http://overpass.osm.rambler.ru/cgi/xapi_meta? *[bbox=11.54,48.14,11.543,48.145]') YIELD value UNWIND value["_children"]
AS child WITH child WHERE child["_type"] = "node" WITH child.id AS id,   child.lat AS latitude,   child.lon AS longitude,   child["user"] AS userName MERGE (point:Point {id: id}) SET point.latitude = latitude,   point.longitude = longitude MERGE (user:User {name: userName}) MERGE (user)-[:EDITED]->(point)

Load JSON

apoc.load.json WITH "https://api.stackexchange.com/2.2/questions? pagesize=100&order=desc&sort=creation&tagged=neo4j&site=stackoverflow&filter=!5-i6Zw8Y)4W7vpy91PMYsKM- k9yzEsSC1_Uxlf" AS url CALL apoc.load.json(url) YIELD
value UNWIND value.items AS q MERGE (question:Question {id:q.question_id})   ON CREATE SET question.title = q.title,   question.share_link = q.share_link,   question.favorite_count = q.favorite_count MERGE (owner:User {id:q.owner.user_id})   ON CREATE SET owner.display_name = q.owner.display_name  MERGE (owner)-[:ASKED]->(question) FOREACH (tagName IN q.tags |   MERGE (tag:Tag {name:tagName}) MERGE (question)-[:TAGGED]->(tag))  FOREACH (a IN q.answers | MERGE (question)<-[:ANSWERS]-(answer:Answer {id:a.answer_id}) MERGE (answerer:User {id:a.owner.user_id})   ON CREATE SET answerer.display_name = a.owner.display_name   MERGE (answer)<-[:PROVIDED]-(answerer))

WITH "https://api.stackexchange.com/2.2/questions?pagesize=100&order=desc&sort=creation&tagged=neo4j&site=stackoverflow&filter=!5- i6Zw8Y)4W7vpy91PMYsKM-k9yzEsSC1_Uxlf" AS url CALL apoc.load.json(url) YIELD value UNWIND
value.items AS q MERGE (question:Question {id:q.question_id})   ON CREATE SET question.title = q.title,   question.share_link = q.share_link,   question.favorite_count = q.favorite_count MERGE (owner:User {id:q.owner.user_id})   ON CREATE SET owner.display_name = q.owner.display_name  MERGE (owner)-[:ASKED]->(question) FOREACH (tagName IN q.tags |   MERGE (tag:Tag {name:tagName}) MERGE (question)-[:TAGGED]->(tag))  FOREACH (a IN q.answers | MERGE (question)<-[:ANSWERS]-(answer:Answer {id:a.answer_id}) MERGE (answerer:User {id:a.owner.user_id})   ON CREATE SET answerer.display_name = a.owner.display_name   MERGE (answer)<-[:PROVIDED]-(answerer)) Use FOREACH for arrays within a row

APOC - Graph Refactoring

apoc.refactor.mergeNodes MATCH (n:Person) WITH n.email AS email, collect(n) as people
WHERE size(people) > 1 CALL apoc.refactor.mergeNodes(people) YIELD node RETURN node

apoc.create.addLabels MATCH (n:Movie) CALL apoc.create.addLabels(id(n), [n.genre]) YIELD node REMOVE node.genre
RETURN node

apoc.create.addLabels MATCH (n:Movie) CALL apoc.create.addLabels( id(n), [ n.genre ] )
YIELD node REMOVE node.genre RETURN node

APOC - Cypher Execution

Run large scale updates CALL apoc.periodic.iterate( 'MATCH (n:Person) RETURN n',
'SET n.name = n.firstName + " " + n.lastName',  {batchSize:10000, parallel:true})

APOC - Utility Functions

Compute soundex encoding of a string CALL apoc.text.phonetic('Hello, dear User!')
YIELD value RETURN value   // will return 'H436'

How similar do two strings sound? CALL apoc.text.phoneticDelta(  'Hello Mr
Rabbit', 'Hello Mr Ribbit')   // will return '4' (very similar)

Extract domain names WITH 'http://www.example.com/all-the-things' AS url RETURN apoc.data.domain(url) //
will return 'www.example.com'

Date to Timestamp RETURN apoc.date.parse(  '2015/03/25 03:15:59',  's',   'yyyy/MM/dd
HH:mm:ss'  )    // will return 1427253359

Timestamp to Date RETURN apoc.date.format(  1427253359,   's',   'yyyy/MM/dd
HH:mm:ss'  )   // will return "2015/03/25 03:15:59"

And many more! https://neo4j-contrib.github.io/neo4j-apoc-procedures/

Kafka and Neo4j

Functionality • Still in development! • Stream transaction event handler
events to a Kafka topic • Read Kafka records from given topic(s) • Treat records as input parameters • Uses configured Cypher statements to merge into the graph

What Do I Need? • Configuration properties • Set up
node-patterns to send to Kafka • Choose Labels and properties to include/exclude • Patterns separated by semicolon

neo4j.conf kafka.zookeeper.connect=localhost:2181 kafka.bootstrap.servers=localhost:9092 kafka.acks=1 kafka.num.partitions=1 kafka.retries=2 kafka.batch.size=16384 kafka.buffer.memory=33554432 kafka.reindex.batch.size=1000 kafka.session.timeout.ms=15000
kafka.connection.timeout.ms=10000 kafka.replication=1 kafka.group.id=neo4j kafka.topics=neo4j kafka.patterns=neo4j:*

Label & Property Setup kafka.topics=topic1,topic2 kafka.patterns=topic1:*;topic2:Label1 {prop1, prop2}, topic1:Label1:Label2{*,-prop1}, topic2:Label3{-prop1,-prop2,prop3}

RDF data into Neo4j

Import RDF triples

semantics.importRDF CALL semantics.importRDF("file:///industry.ntriples","N-Triples", {})

Thomson Reuters' OpenPermID Graph

Graph-Aided Search

conf/neo4j.conf com.graphaware.runtime.enabled=true    #ES becomes the module ID:  com.graphaware.module.ES. 2=com.graphaware.module.es.ElasticSearchModuleBootstrapper 
  #URI of Elasticsearch  com.graphaware.module.ES.uri=localhost    #Port of Elasticsearch  com.graphaware.module.ES.port=9201

Find nodes CALL ga.es.queryNode(‘{\"query\": {\"match\":{\"name\":=\"alessandro\"}}}') YIELD node, score RETURN node,
score

Find relationships CALL ga.es.queryRelationship(‘{\"query\": {\"match\":{\"city\":\"paris\"}}}') YIELD relationship, score RETURN relationship,
score

dzone.com/refcardz/graph-powered-search-neo4j-amp-elasticsearch

Versioned Graphs

Create node CALL graph.versioner.init('Person',   {ssn: 123456789, name: 'Marco'},  
{address: 'Via Roma 11'}  )

Immutable properties CALL graph.versioner.init('Person',   {ssn: 123456789, name: 'Marco'},  

State properties CALL graph.versioner.init('Person',   {ssn: 123456789, name: 'Marco'},  

Update state MATCH (p:Person {name: "Marco"}) WITH p CALL graph.versioner.update(p,
{address: 'Via Roma 12'}) YIELD node RETURN node

Pass in the new state MATCH (p:Person {name: "Marco"}) WITH
p CALL graph.versioner.update(p, {address: 'Via Roma 12'}) YIELD node RETURN node

Spatial

Create spatial index CALL spatial.addWKTLayer('geom', 'wkt')

Add spatial property to nodes CREATE (d:District {...}) SET d.wkt
= 'MULTIPOLYGON(((23.22, ... )))'

Add nodes to spatial index MATCH (d:District) WITH collect(d) AS
districts CALL spatial.addNodes('geom', districts) YIELD node RETURN count(*)

Query nodes by location CALL spatial.withinDistance('geom',  {latitude: 37.563440, longitude: -122.322265},
1)   YIELD node AS d WITH d, d.wkt AS wkt, d.state AS state, d.district AS district LIMIT 1 MATCH (d)<-[:REPRESENTS]-(l:Legislator) MATCH (l)-[:SERVES_ON]->(c:Committee) MATCH (c)<-[:REFERRED_TO]-(b:Bill) MATCH (b)-[:DEALS_WITH]->(s:Subject) RETURN *

Finds nodes within 1km CALL spatial.withinDistance('geom',  {latitude: 37.563440, longitude: -122.322265},
1)   YIELD node AS d WITH d, d.wkt AS wkt, d.state AS state, d.district AS district LIMIT 1 MATCH (d)<-[:REPRESENTS]-(l:Legislator) MATCH (l)-[:SERVES_ON]->(c:Committee) MATCH (c)<-[:REFERRED_TO]-(b:Bill) MATCH (b)-[:DEALS_WITH]->(s:Subject) RETURN *

Continue with the rest of the query CALL spatial.withinDistance('geom',  {latitude:
37.563440, longitude: -122.322265}, 1)   YIELD node AS d WITH d, d.wkt AS wkt, d.state AS state, d.district AS district LIMIT 1 MATCH (d)<-[:REPRESENTS]-(l:Legislator) MATCH (l)-[:SERVES_ON]->(c:Committee) MATCH (c)<-[:REFERRED_TO]-(b:Bill) MATCH (b)-[:DEALS_WITH]->(s:Subject) RETURN *

lyonwj.com/2016/08/09/neo4j-spatial-procedures- congressional-boundaries/

Graph-based Machine Learning

Annotating text CREATE (n:News) SET n.text = "Scores of people
were already lying dead or injured inside a crowded Orlando nightclub, and the police had spent hours trying to connect with the gunman and end the situation without further violence. But when Omar Mateen threatened to set off explosives, the police decided to act, and pushed their way through a wall to end the bloody standoff."

Annotating text MATCH (n:News) CALL ga.nlp.annotate({text: n.text, id: id(n)}) YIELD
result MERGE (n)-[:HAS_ANNOTATED_TEXT]->(result) RETURN result

Execute procedure MATCH (n:News) CALL ga.nlp.annotate({text: n.text, id: id(n)}) YIELD
result MERGE (n)-[:HAS_ANNOTATED_TEXT]->(result) RETURN result

Relate to text node MATCH (n:News) CALL ga.nlp.annotate({text: n.text, id:
id(n)}) YIELD result MERGE (n)-[:HAS_ANNOTATED_TEXT]->(result) RETURN result

Graph Algorithms

Insights from Algorithms

Graph of Thrones

• Single Source Short Path • All Pairs SSP •
Parallel BFS / DFS • Minimum Weight Spanning Tree • Shortest Path • A* • Yen’s K-shortest paths • Random Walk • Strongly-Connected Components • Union Find / WCC • Label Propagation • Louvain • Triangle-Count / Clustering Coefficent • PageRank (baseline) • Betweeness • Closeness • Degree • Harmonic (new!) https://neo4j.com/docs/graph-algorithms/current/

Usage 1.Call as Cypher procedure 2.Pass in specification (Label, Prop,
Query) and configuration 3.Execute and return results A. ~.stream variant returns (a lot) of results CALL algo.<name>.stream('Label','TYPE', {conf}) YIELD nodeId, score B. non-stream variant writes results to graph and returns statistics  CALL algo.<name>('Label','TYPE', {conf})

Cypher Projection Pass in Cypher statement for node and relationship
lists.   CALL algo.<name>( 'MATCH ... RETURN id(n)', 'MATCH (n)-->(m) RETURN id(n) as source, id(m) as target',   {graph:'cypher'})

Graph Algorithms Sandbox neo4j.com/sandbox

Graph ML Models

What’s In It? • Linear regression (Lauren Shin) • Multiple
linear regression (Lauren Shin) • DeepGL/DeepWalk (Mark Needham) • …more coming soon!

https://towardsdatascience.com/graphs-and-linear-regression-734d1446e9cd

Graph Visualization

var viz; function draw() { var config = { container_id:
"viz", server_url: "bolt://localhost:7687", server_user: "neo4j", server_password: "sorts-swims-burglaries", labels: { "Character": { "caption": "name", "size": "pagerank", "community": "community" } }, relationships: { "INTERACTS": { "thickness": "weight", "caption": false } }, initial_cypher: "MATCH (n)-[r:INTERACTS]->(m) RETURN *" }; viz = new NeoVis.default(config); viz.render(); }

GraphQL

What is it? GraphQL is a query language for your
API, and a server-side runtime for executing queries by using a type system you define for your data.

API, and a server- side runtime for executing queries by using a type system you define for your data.

API, and a server-side runtime for executing queries by using a type system you define for your data.

API, and a server-side runtime for executing queries by using a type system you define for your data. type Planet {  name: String  climate: String  } type Character {  name: String  friends: [Character]  homeWorld: Planet  species: Species  } type Species {  name: String  lifespan: Int  origin: Planet  }

Manual mapping code

Auto translating GraphQL → Cypher github.com/neo4j-graphql/neo4j-graphql github.com/neo4j-graphql/neo4j-graphql-js

Server-side Java extension

conf/neo4j.conf dbms.unmanaged_extension_classes=org.neo4j.graphql=/graphql  dbms.security.procedures.whitelist=graphql.*

CALL graphql.idl('  type Movie { title: String! released: Int actors:
[Person] @relation(name:"ACTED_IN",direction:IN) } type Person { name: String! born: Int movies: [Movie] @relation(name:"ACTED_IN") }' )

WITH '{ Person(born: 1961) { name, born } }' as
query, {} as params CALL graphql.execute(query,params)   YIELD result UNWIND result.Person as p RETURN p.name, p.born

Javascript extension

import {neo4jgraphql} from 'neo4j-graphql-js'; const resolvers = { Query: {
Movie(object, params, ctx, resolveInfo) { return neo4jgraphql(object, params, ctx, resolveInfo); } } };

The GRAND stack

The GRAND stack GraphQL  React  Apollo  Neo4j Database

dzone.com/refcardz/an-overview-of-graphql

How do I find out about more cool stuff???

This Week in Neo4j - Developer Update neo4j.com/tag/twin4j

Neo4j Community Site!

(you)-[:HAVE]->(questions)<-[:ANSWERS]-(jennifer) @JMHReif [email protected]

How many did we cover? • Bolt drivers: https://neo4j.com/developer/language-guides/ •
User-defined procs/funcs: https://neo4j.com/developer/procedures-functions/ • APOC: https://github.com/neo4j-contrib/neo4j-apoc-procedures • Neo4j/Kafka: https://github.com/neo4j-contrib/neo4j-streams • Neo4j/RDF: https://github.com/jbarrasa/neosemantics • Neo4j/Elasticsearch: https://github.com/graphaware/neo4j-to-elasticsearch • Versioned graphs: https://github.com/h-omer/neo4j-versioner-core • Spatial: https://github.com/neo4j-contrib/spatial • NLP: https://github.com/graphaware/neo4j-nlp • Graph Algorithms: https://github.com/neo4j-contrib/neo4j-graph-algorithms • ML models: https://github.com/neo4j-graph-analytics/ml-models • Graph Visualization: https://github.com/neo4j-contrib/neovis.js • GraphQL/GRANDstack: https://github.com/neo4j-graphql

Extensibility for Java Developers in Neo4j

Extensibility for Java Developers in Neo4j

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