![Graph Algorithms
• shortestPath()
MATCH p =
ShortestPath
( (keanu:Person)-[:KNOWS*]-(kevin:Person) )
WHERE
keanu.name="Keanu Reeves"
and
kevin.name = "Kevin Bacon"
RETURN
length(p)
25](https://image.slidesharecdn.com/neo4jtms-140824134242-phpapp01/85/Neo4j-tms-25-320.jpg)
Neo4j tms
- 1. Neo4j Graph DB {A step ahead towards non-RDBMS} Presented By: Mangal Dev 1
- 2. Agenda • N0SQL • Graph Database • Neo4J • Samples Brew install neo4j 2
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- 4. Interdependency and complexity of data.Informationconnectivity Text Documents Hypertext Feeds Blogs Wikis UGC Tagging RDFa Social networks 4
- 5. NOSQL Categories Key-Values Stores Dynamo Riak Column Family Stores Big Table -> Google Casandra -> Facebook HBase -> Apache Document Based DB CouchDB MongoDB Graph Databases. AllegroDB FlockDB -> Twitter InfiniteGraph Neo4j Sones 5
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- 8. Why GraphDB ? • Flexibility No Normalization/De-normalization Relational databases deal poorly with relationships. • Agility Schema free nature Foreign Keys turns into dangling refrences • Reciprocal Queries • Usecases SocialNetworks BioInformatics DataManagement NetworkManagement CloudManagement GeoData What does ‘R’ stand for in RDBMS ? 8
- 10. Property Graph Model WORKS_FOR Name: Gracenote first name: Neeti first name: Mangal late name: Dev first name: Rajan Name: Bangalore 10
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- 12. Database full of linked nodes Stores data as nodes and relationships 12
- 13. Some More Info.. • Widely Used • Full ACID transactions • Schema free, bottom-up data model design • It’s a stable and in active developlment since mid 2000 • High Performance, can cover upto 2 billion nodes. • Lot of Bindings 13
- 14. How do you query and work with this graph database? • Run it as – Embedded – Standalone • Query it with – Cyhper from Neo4j Browser – Cypher from Java – Rest API – Rest API using Cypher query – Programatically – Gremlin 14
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- 16. Cypher Query • MATCH – Matches the graph pattern in the real graph. • WHERE – Filters using predicates or anchors pattern elements. • RETURN – Returns and projects result data, also handles aggregation. • ORDER BY – Sorts the query result. • SKIP/LIMIT – Paginates the query result. 16
- 17. Go to Console… • Neo4j start • Go to url : – http://localhost:7474/browser/ 17
- 18. Cypher Basics 18
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- 23. Core API Neo4j Logical Architecture REST API JVM Language Bindings Traversal Framework Caches Memory-Mapped (N)IO Filesystem Java Ruby Clojure… Graph Matching 23
- 24. Graph Algorithms • algorithm can have one of these values: – shortestPath – allSimplePaths – allPaths – dijkstra (optionally with cost_property and default_cost parameters) 24
- 25. Graph Algorithms • shortestPath() MATCH p = ShortestPath ( (keanu:Person)-[:KNOWS*]-(kevin:Person) ) WHERE keanu.name="Keanu Reeves" and kevin.name = "Kevin Bacon" RETURN length(p) 25
- 26. Indexing a Graph? • Graphs are their own indexes! • But sometimes we want short-cuts to well- known nodes • Can do this in our own code – Just keep a reference to any interesting nodes e.g. CREATE INDEX ON :MOVIE(title); Don’t index every node! 26
- 27. Inbuilt Lucene Support • Default index implementation for Neo4j • Each index supports nodes or relationships • Supports exact and regex-based matching – Query(‘index_name’,’pattern’) • Supports scoring – Number of hits in the index for a given item – Great for recommendations! 27
- 28. Scalability • The HA component supports master-slave replication • But Scaling graphs are HARD. • Acc to Emil -> Superb performance till some billions of nodes 28
- 30. Pros and Cons • Strengths – Powerful data model – Fast • For connected data, can be many orders of magnitude faster than RDBMS • Weaknesses: – Sharding • Though they can scale reasonably well • And for some domains you can shard too! 30
- 32. Sample Exercises • Find all Persons who killed other in Mahabharat. • Find movies in which actor has acted along with directed it. • the five actors who have acted in the most movies • Shortest path between Kunti and Sehdev • Find persons got killed by Kunti’s sons 32
- 33. References • http://www.neo4j.org/learn/online_course • http://www.infoq.com/articles/graph-nosql- neo4j • http://www.manning.com/partner/Neo4J_me ap_ch01.pdf 33
Editor's Notes
- #4: The exponential growth of the volume of data generated by users, systems and sensors, further accelerated by some big distributed systems like Amazon, Google and other cloud services. Every minute some systems are persisting around GBs of data . Quora Facebook example
- #5: The increasing interdependency and complexity of data, accelerated by the Internet, Web2.0, social networks and open and standardized access to data sources from a large number of different systems.
- #9: individual, isolated, and discrete data items, but also the connections between them And while we could easily fit the discrete data in relational tables, the connected data was more challenging to store and tremendously slow to query. the property graph model intuitive and easy to understand.