Graph Data Store

Database that embraces relationships as a core aspect of its data model is able to store, process, and query connections efficiently. While other databases compute relationships expensively at query time, a graph database stores connections as first class citizens, readily available for any "join-like" navigation operation. Accessing those already persistent connections is an efficient, constant-time operation and allows you to quickly traverse millions of connections per second per core.

Graph Data Store

Dexlock

Titan

Titan is a transactional database that can support thousands of concurrent users executing complex graph traversals in real time.Titan has the ability to use Cassandra/HBase etc for storage and ElasticSearch for indexing. .It is basically a scalable graph processing over big data processing systems

Dexlock

Neo4J

Graph database capable of holding very large amounts of data. On of the key feature of Neo4j is that programmers works with a flexible network structure of nodes and relationships rather than static tables yet enjoys all the benefits of enterprise quality database.