What is a Graph Database?
A graph database is an online database management system with Create, Read, Update and Delete (CRUD) operations working on a graph data model.

Unlike other databases, relationships take first priority in graph databases. This means your application doesn’t have to infer data connections using things like foreign keys or out-of-band processing, such as MapReduce.

The data model for a graph database is also significantly simpler and more expressive than those of relational or other NoSQL databases.

Graph databases are built for use with transactional (OLTP) systems and are engineered with transactional integrity and operational availability in mind.