Chapter 6
Neo4J

A bungee cord is a helpful tool because you can use it to tie together the most disparate of things, no matter how awkwardly shaped or ill fitting they may be. In a lot of ways, Neo4j is the bungee cord of databases, a system intended not so much to store information about things as to tie them together and record their connections with each other.

Neo4j is a member of a family of databases known as graph databases because it stores data as a graph (in the mathematical sense). Neo4j is known for being “whiteboard friendly” because virtually any diagram that you can draw using boxes and lines on a whiteboard can be stored in Neo4j.

Neo4j focuses more on the relationships between values than on the commonalities among sets of values (such as collections of documents or tables of rows). In this way, it can store highly variable data in a natural and straightforward way.

On one side of the scale spectrum, Neo4j is small enough to be embedded into nearly any application; on the other side of the spectrum, Neo4j can run in large clusters of servers using master-slave replication and store tens of billions of nodes and as many relationships. In other words, Neo4j can handle just about any size problem that you can throw at it.