Pouring Coffee into the Matrix – Building Java Applications on Neo4j

Many of us have built applications for traditional data structures (like relational database tables), but is it different for graph data stores? Do developers need to retool and relearn? In this session, we will cover a brief intro to graphs, walk through writing a typical Java application with Spring, and then connect it to a graph database. From interacting with the graph data from the application to deploying to the cloud, we will see the process from start to finish. We will learn how to tackle pitfalls and pick up tips along the way, as well as explore the ways we can build, deploy, and connect applications to the database. This will come alive through a live demo, as we see the results of our efforts. Come to this session to build your business applications for graph data!

Code: https://github.com/JMHReif/pouring-coffee-into-matrix

Transcript

1. Pouring Coffee into the Matrix Building Java applications on Neo4j Jennifer Reif jennifer.reif@neo4j.com @JMHReif github.com/JMHReif jmhreif.com linkedin.com/in/jmhreif
2. Who is Jennifer Reif? Developer Advocate, Neo4j • Continuous learner • Conference speaker • Tech blogger • Other: geek Jennifer Reif jennifer.reif@neo4j.com @JMHReif github.com/JMHReif jmhreif.com linkedin.com/in/jmhreif
3. What is graph?
4. What is graph? • Database - data storage • Way to store relationships with entities • Powerful when… • Queried - results based on the network structure • Visualized - depth comprehension of network • Utilized in algorithms/pipelines - factoring network into calculations
5. Graph history • Much older than technology… • Arose from solution need (then and now) Seven Bridges of Konigsberg problem. Leonhard Euler, 1735
6. Graph Data Model
7. Property graph • Node (vertex) • Relationship (edge)
8. Nodes • Represent objects or entities • Can be labeled Category Feature JavaVersion
9. Nodes • Represent objects or entities • Can be labeled • May have properties Category Feature JavaVersion version: “17” gaDate: 2021-09-14 name: “lang” title: “Pattern Matching for switch”
10. Relationships • Must have a type • Must have a direction (stored) • Can be read in either direction Category Feature JavaVersion version: “17” gaDate: 2021-09-14 INCLUDES BELONGS_TO name: “lang” title: “Pattern Matching for switch”
11. Relationships • Must have a type • Must have a direction (stored) • Can be read in either direction • May have properties Category Feature JavaVersion version: “17” gaDate: 2021-09-14 INCLUDES BELONGS_TO featureCount: 3 CHANGES name: “lang” title: “Pattern Matching for switch”
12. Relationships • Must have a type • Must have a direction (stored) • Can be read in either direction • May have properties • Nodes can have multiple relationships Category Feature JavaVersion version: “17” gaDate: 2021-09-14 INCLUDES BELONGS_TO featureCount: 3 CHANGES STARTED_IN name: “lang” title: “Pattern Matching for switch” IM PACTED_BY
13. Label • Group of nodes • Like a category • Domain class :) Person
14. Label • Group of nodes • Like a category • Domain class :) • Inheritance :) Person Employee Customer
15. Properties • Key-value pair • Associated with node or relationship • Like a variable name and value Category JavaVersion version: “17” CHANGES gaDate: 2021-09-14 featureCount: 3 version: “6” codeName: “Mustang”
16. Modeling
17. Whiteboard friendliness
18. Graph data
19. Java dev: why graph?
20. Answering data questions • Java versions (i.e. 8, 11, 17) • Changes between versions over time • Di ff s • History for one speci fi c feature
21. Domain/Application alignment • Class • Entity/Object • Represents domain type • Variables/Properties • Details for that entity • Constructor - instance of object • Each instance is unique object with varying info @Node public class JavaVersion { @Id @Property("version") private fi nal String javaVersion; private String name, codeName, status, apiSpec; private LocalDate gaDate, eolDate; }
22. Retaining relationships • Adding relationships • Add variable as pointer to another object • Links entities together • Might have some annotations for mapping @Node public class JavaVersion { @Relationship(“FROM_NEWER”) private List<VersionDiff> olderVersionDiffs; }
23. Prep for code!
24. Neo4j - cloud AuraDB • Free tier • Java language version data loaded
25. Language drivers • Neo4j Java driver (o ffi cial) • Spring Data Neo4j (SDN) • Includes Java driver dependency • Other options: • O ffi cial drivers -> Python, JavaScript, Go, .NET • Java frameworks -> Quarkus, Helidon, Micronaut, etc
26. Spring provisions • Spring Initializr • SB reduce boilerplate • Annotation-based OGM for POJOs • Query derivation + DSL for custom (Cypher) • Spring Data easy-connect to Neo4j
27. Let’s code!
29. Resources • Code: github.com/JMHReif/pouring-co ff ee-into-matrix • Spring Data Neo4j docs: dev.neo4j.com/sdn-docs • Neo4j AuraDB: dev.neo4j.com/aura-java • NODES: dev.neo4j.com/nodes24 Jennifer Reif jennifer.reif@neo4j.com @JMHReif github.com/JMHReif jmhreif.com linkedin.com/in/jmhreif