Simply put, a graph database is a database that is built on top of a graph data structure. Graph databases store nodes and edges between nodes. Each node and edge is uniquely identified and may contain properties (for example, name, country, age, and so on). An edge also has a label that defines the relationship between two nodes.

Graph databases exhibit the same schema flexibility, which is a huge advantage, given that current schemas are liable to change: you can add new nodes without affecting existing ones. This flexibility makes them appropriate for agile development. They are very good for retrieving highly related data. Queries in graph databases are intuitive and similar to the human brain.