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 and walk through writing a typical Java application with Spring and connect it to a graph database. We will walk through interacting with the graph data from the application, and show it in the cloud, as well. Come to this session to apply your business applications to graph data!

Transcript

1. Jennifer Reif
   Email: jennifer.reif@neo4j.com
   Twitter: @JMHReif
   LinkedIn: linkedin.com/in/jmhreif
   Github: GitHub.com/JMHReif
   Website: jmhreif.com
   Pouring Coffee into the Matrix
   Building Java applications on Neo4j
   

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2. Who Am I?
   • Developer + Advocate
   
   • Continuous learner
   
   • Technical content writer
   
   • Conference speaker
   
   • Other: geek
   Jennifer Reif
   Email: jennifer.reif@neo4j.com
   Twitter: @JMHReif
   LinkedIn: linkedin.com/in/jmhreif
   Github: GitHub.com/JMHReif
   Website: jmhreif.com
   

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3. What is graph?
   

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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
   

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5. Graph History
   • Graph much older than technology of the last decade…
   
   • Arose from solution need (then and now)
   Seven Bridges of Konigsberg problem. Leonhard Euler, 1735
   

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6. Graph Data Model
   

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7. Property Graph
   • Node (vertex)
   
   • Relationship (edge)
   

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8. Nodes
   • Represent objects or entities
   
   • Can be labeled
   JavaVersion
   VersionDiff
   JavaVersion
   

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9. Nodes
   • Represent objects or entities
   
   • Can be labeled
   
   • May have properties
   JavaVersion
   VersionDiff
   JavaVersion
   version: “17”
   
   
   gaDate: 2021-09-14
   fromVersion: “17.0.3+7-tem”
   
   
   toVersion: “1.6.0_45-oracle”
   version: “6”
   
   
   gaDate: 2006-12-12
   
   
   codeName: “Mustang”
   

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10. Relationships
    • Must have a type
    
    • Must have a direction
    JavaVersion
    VersionDiff
    JavaVersion
    version: “17”
    
    
    

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11. Relationships
    • Must have a type
    
    • Must have a direction
    
    • May have properties
    JavaVersion
    VersionDiff
    JavaVersion
    version: “17”
    
    
    

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12. Relationships
    • Must have a type
    
    • Must have a direction
    
    • May have properties
    
    • Nodes can share multiple relationships
    JavaVersion
    VersionDiff
    JavaVersion
    version: “17”
    
    
    

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13. Label
    • A group of nodes
    
    • Like a category
    
    • Domain class :)
    Person
    

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14. Label
    • A group of nodes
    
    • Like a category
    
    • Domain class :)
    
    • Inheritance :)
    Person
    Employee
    Customer
    

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15. Properties
    • Key-value pair
    
    • Associated with node or relationship
    
    • Like a variable name and value
    JavaVersion
    JavaVersion
    version: “17”
    version: “6”
    versionSteps: 3
    M
    IG
    RATES
    gaDate: 2021-09-14
    gaDate: 2006-12-12
    codeName: “Mustang”
    

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16. Modeling
    

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17. Whiteboard friendliness
    

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18. Graph data
    

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19. Developing applications
    

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20. Java App Data Store Options
    • Relational
    
    • Straight JDBC
    
    • JDBC Template
    
    • JOOQ
    
    • JPA or Hibernate
    
    • NoSQL - Document
    
    • MongoDB
    
    • Graph
    
    • Neo4j
    

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21. Java Dev: Why Graph?
    

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22. 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
    

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23. Domain/Application alignment
    • Class
    
    • Entity/Object
    
    • Represents domain type
    
    • General outline for objects of that type
    
    • Variables/Properties
    
    • Details for that entity
    
    • Values may not always exist
    
    • Constructor - instance of object
    
    • Each instance is unique object with varying info
    @Node
    @Data
    @RequiredArgsConstructor
    public class JavaVersion {
    @Id
    @Property("version")
    private
    fi
    nal String javaVersion;
    private String name, codeName, status, apiSpec;
    private LocalDate gaDate, eolDate;
    }
    

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24. Retaining Relationships
    • Adding relationships
    
    • Add variable as pointer to another object
    
    • Links entities together
    
    • Might have some annotations for mapping @Node
    @Data
    @RequiredArgsConstructor
    public class JavaVersion {
    @Relationship(“FROM_NEWER”)
    private List olderVersionDiffs;
    }
    

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25. • Set theory - rows and columns
    
    • Schema - rigid, enforced
    
    • Entities - table row
    
    • Metadata - columns
    
    • Relationships - crafted JOINs
    
    • Queries - JOINs at runtime
    
    • Indexes - Lookups scans
    Graphs for Java devs
    • Graph theory - entity network
    
    • Schema -
    fl
    exible, optional
    
    • Entities - node (object)
    
    • Metadata - properties
    
    • Relationships - stored joins
    
    • Queries - joins at write
    
    • Indexes - place to start
    Relational database Graph database
    

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26. • Links stored as primary/foreign keys
    
    • Traversal expressed as nested
    subqueries
    
    • Every subquery needs separate query
    plan
    Relational vs Graph
    • Links stored as pointers (IFA)
    
    • Traversal expressed as single pattern
    
    • One query plan for entire path
    

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27. Demo Background
    

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28. Neo4j AuraDB
    • Free tier instance
    
    • Java language version data loaded
    

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29. Language drivers
    • Neo4j Java driver (o
    ffi
    cial)
    
    • Spring Data Neo4j
    
    • Uses Neo4j Java driver at base
    
    • Other options:
    
    • O
    ffi
    cial drivers-> Python, JavaScript, Go, .NET
    
    • Java frameworks-> Quarkus, Helidon, Micronaut, etc
    

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30. Spring provisions
    • Spring Initializr
    
    • Spring Boot’s reduction of boilerplate
    
    • Annotation-based OGM for POJOs
    
    • Query derivation + DSL for custom (Cypher)
    
    • Spring Data’s easy connection to Neo4j
    
    • BOLT or HTTP
    

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31. Let’s see some code!
    Demo time!
    

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32. Resources
    • Source code: github.com/JMHReif/pouring-co
    ff
    ee-into-matrix-lombok
    
    • Spring Data Neo4j documentation: dev.neo4j.com/sdn-docs
    
    • Neo4j AuraDB: dev.neo4j.com/aura-java
    
    • Blog: bit.ly/jmhreif-blog
    
    • NODES: dev.neo4j.com/nodes
    Jennifer Reif
    Email: jennifer.reif@neo4j.com
    Twitter: @JMHReif
    LinkedIn: linkedin.com/in/jmhreif
    Github: GitHub.com/JMHReif
    Website: jmhreif.com DON’T MISS!
    

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