Neo4j – open-source graph database

Neo4j is an open source embedded, disk-based, fully transactional Java persistence engine that uses graph rather then tables to store your data. it’s an high performance graph engine which have flexible data structure that allows a more agile and rapid style of development.

it offer a massive scalability and uses simple graph building blocks such as nodes, relationships and key-value properties on a single machine and can be scaled across multiple machines. This allows software developers to work with a flexible, dynamic, object-oriented data structure rather than forcing their domain data into strict and static tables.

Neo4J is a free graph database released under a dual free software/commercial license model (which basically means that it’s open source under the AGPLv3 but if you’re interested in using it with closed source software, then you must buy a commercial license).

Features of Neo4j

1. An Intuitive graph-oriented model for data representation. Instead of static and rigid tables, rows and columns, you work with a flexible graph network consisting of nodes, relationships and properties.
2. a disk-based, native storage manager completely optimized for storing graph structures for maximum performance and scalability.
3. massive scalability. Neo4j can handle graphs of several billion nodes/relationships/properties on a single machine and can be scaled across multiple machines.
4. a powerful traversal framework for high-speed traversals in the node space.
5. a small footprint. Neo4j is a single <500k jar with one dependency (the Java Transaction API).
6. a simple and convenient object-oriented API.

Download : Neo4j graph database