#### Graph database

<p align="center">
  <img src="images/fNcl65g.png">
  <br/>
  <i><a href=https://en.wikipedia.org/wiki/File:GraphDatabase_PropertyGraph.png>Source: Graph database</a></i>
</p>

> Abstraction: graph

In a graph database, each node is a record and each arc is a relationship between two nodes.  Graph databases are optimized to represent complex relationships with many foreign keys or many-to-many relationships.

Graphs databases offer high performance for data models with complex relationships, such as a social network.  They are relatively new and are not yet widely-used; it might be more difficult to find development tools and resources.  Many graphs can only be accessed with [REST APIs](#representational-state-transfer-rest).

##### Source(s) and further reading: graph

* [Graph database](https://en.wikipedia.org/wiki/Graph_database)
* [Neo4j](https://neo4j.com/)
* [FlockDB](https://blog.twitter.com/2010/introducing-flockdb)