Application modelling with graph databases
Applications are built around domain and business concepts. As developers, we model these concepts and their relationships all the time in our heads, on whiteboards, and in code. Then we perform mental gymnastics translating objects and relationships into tables, rows and columns. Wouldn't it be better if our data storage thought the same way we do? This talk will describe a few types of problems that relational databases and many contemporary NOSQL solutions have trouble modeling, and how graph databases are a solution to those problems. Along the way, attendees will be introduced to the graph database Neo4j, will see how to interact with it via the Cypher query language, and learn how they can start modeling their own application domains as graphs.
![Back to Bacon
MATCH p = shortestPath( (r:Actor) - [*] - (b:Actor) )
WHERE r.name=Keanu Reeves AND b.name=Kevin Bacon
RETURN p, LENGTH(p)/2](https://image.slidesharecdn.com/applicationmodellingwithgraphdatabases-cypher-140117203400-phpapp02/85/Application-modelling-with-graph-databases-14-320.jpg)
![Social
MATCH
(:Person {name:"Josh"})-[:FRIEND_OF]-(p:Person),
(m:Movie)
WHERE NOT
(p)-[:HAS_WATCHED]->(m)
RETURN COUNT(p) as not_seen, m
ORDER BY not_seen DESC LIMIT 1](https://image.slidesharecdn.com/applicationmodellingwithgraphdatabases-cypher-140117203400-phpapp02/85/Application-modelling-with-graph-databases-15-320.jpg)
Application modelling with graph databases
- 1. Application Modeling with Graph Databases
- 3. The Problem
- 4. The Solution? > -- First degree > SELECT actor_name FROM cast WHERE movie_title IN (SELECT DISTINCT movie_title FROM cast WHERE actor_name='Kevin Bacon') > -- Second degree > SELECT actor_name FROM cast WHERE movie_title IN (SELECT DISTINCT movie_title FROM cast WHERE actor_name IN (SELECT actor_name FROM cast WHERE movie_title IN (SELECT DISTINCT movie_title FROM cast WHERE actor_name='Kevin Bacon'))) > -- Third degree > SELECT actor_name FROM cast WHERE movie_title IN(SELECT DISTINCT movie_title FROM cast WHERE actor_name IN (SELECT actor_name FROM cast WHERE movie_title IN (SELECT DISTINCT movie_title FROM cast WHERE actor_name IN (SELECT actor_name FROM cast WHERE movie_title IN (SELECT DISTINCT movie_title FROM cast WHERE actor_name='Kevin Bacon'))))
- 5. The Truth Relational databases aren't very good with relationships Data RDBMs
- 6. Try again?
- 8. Warning: Computer Science Ahead A graph is an ordered pair G = (V, E) where V is a set of vertices and E is a set of edges, which are pairs of vertices in V. If vertex pairs in E are ordered, the graph is directed.
- 9. Property Graph Nodes have properties and labels Relationships have properties, a type and direction Relationships are first-class entities Queried just like Nodes Indexes Unique constraints new in Neo4j 2.0!
- 11. Relational Databases are Graphs!
- 13. Modeling "Whiteboard-Friendly" Nouns => nodes, Verbs => relationships
- 14. Back to Bacon MATCH p = shortestPath( (r:Actor) - [*] - (b:Actor) ) WHERE r.name=Keanu Reeves AND b.name=Kevin Bacon RETURN p, LENGTH(p)/2
- 15. Social MATCH (:Person {name:"Josh"})-[:FRIEND_OF]-(p:Person), (m:Movie) WHERE NOT (p)-[:HAS_WATCHED]->(m) RETURN COUNT(p) as not_seen, m ORDER BY not_seen DESC LIMIT 1
- 16. But Wait...There's More! Mutating (insert, update ~ create, merge) Indexing (auto, full-text, spatial) Batches and Transactions Embedded (for JVM) or REST
- 17. Where fore art thou, RDB? Aggregation Ordered data Truly tabular data Few or clearly defined relationships
- 18. Questions?
- 19. Resources http://github.com/jadell/neo4jphp http://neo4j.org Jim Webber - A Little Graph Theory for the Busy Developer http://vimeo.com/76713692 - Jim Webber http://joshadell.com https://joind.in/10430