Neo4j intro

Neo4j is a graph database management system developed by Neo Technology, Inc. Described by its developers as an ACID-compliant transactional database with native graph storage and processing,Neo4j is the most popular graph database according to db-engines.com ^[wikipedia]

I am interested in Neo4j for modelling hierarchies as the RDBMS are not really suited for this ( http://www.codeproject.com/Articles/22824/A-Model-to-Represent-Directed-Acyclic-Graphs-DAG-o)

 Installing Neo4j Community Edition on Windows is a piece of cake: http://neo4j.com/download/
Also there is plenty of documentation and many answered questions on StackOverflow :)

A good place to start: https://www.airpair.com/neo4j/posts/getting-started-with-neo4j-and-cypher

Some useful queries:
--------------------------------
Match Node by id:

MATCH (n)
WHERE id(n) = 14
RETURN n;
---------------------------------
Match relationship by Id

MATCH ()-[r]-() 
WHERE ID(r)=1 
RETURN r 

------------------------------
Find path between 2 nodes, replace "REPORTS_TO" with your relation

START a=node(11), d=node(12)
MATCH p=a-[r:REPORTS_TO*..]-d
RETURN p;
----------------------------
Delete node and all its relationships

MATCH (n { name:'Andres' })
DETACH DELETE n
-----------------------------------------
DELETE all relationships

MATCH  ()-[r:REPORTS_TO]->() DELETE  r;

Importing data from CSV

Official docs: http://neo4j.com/docs/stable/query-load-csv.html

I copied the files to be imported next to the database file because I had issues with other paths. My path looks like: C:\Users\my_user\Documents\Neo4j\file_to_import.csv

Loading nodes:

LOAD CSV FROM 'file:///C:/Users/my_user/Documents/Neo4j/nodes.csv' AS line
CREATE (:User { some_id: line[0], user_name: line[1], link: line[2] })

Add an index on some_id property:

CREATE CONSTRAINT ON (n:User) ASSERT n.some_id IS UNIQUE

Load relations from CSV file, replace PART_OF with your relation:

LOAD CSV  FROM "file:///C:/Users/my_user/Documents/Neo4j/relations.csv" AS line
MATCH (p:User { some_id:line[0] })
MATCH (f:Group { group_id:line[1] })
CREATE (f)-[:PART_OF { some_property: line[2] } ]->(p);