Neo4j

1. Neo4j

2. План • Cypher • Создание • Запросы • Neo4j embedded in Java • Немного о релизации (Neo4j Internals) • Native Graph Processing • Native Graph Storage

3. Neo4j

5. Cypher: Создание CREATE: Creates nodes and relationships.MERGE: Creates nodes uniquely.CREATE UNIQUE: Creates relationships uniquely.DELETE: Removes nodes, relationships.SET: Updates properties and labels.REMOVE: Removes properties and labels.FOREACH: Performs updating actions once per element in a list.WITH: Divides a query into multiple, distinct parts and passes results from one to the next.

6. Cypher: запросы MATCH: Matches the given graph pattern in the graph data.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.

7. Paths • ()-[]->() • ()<-[]-() • ()-[:RelationshipType*N]->() • ()-[]->()<-[]-()

8. Aggregates count(x) Count the number of occurrencesmin(x) Get the lowest valuemax(x) Get the highest valueavg(x) Get the average of a numeric valuesum(x) Sum up valuescollect(x) Collect all the values into an collection

11. Native Graph Storage • Store files: • Nodes • Relationships • Properties • etc • Fixed-sized records (node 9 bytes, rel 33 bytes,…) -> быстрый поиск по ID: • node {id:90} - > в store file его запись начинается с 900 байта - > поиск нода за O(1)

12. Движение по store files Node (9 bytes)

14. Native Graph Processing • Index-free adjacency

15. O(log n)

16. O(1)

17. Источники • http://www.neo4j.org/ • http://docs.neo4j.org/chunked/milestone/ • Ian Robinson, Jim Webber, and Emil EifrémGraph DatabasesThe Definitive Book onGraph Databases