The InfiniteGraph guys put together a page providing a short definition of what graph databases are and what advantages they bring to the table:
“A graph database… uses graph structures with nodes, edges, and properties to represent and store information.”
“Compared with relational databases, graph databases are often faster for associative data sets, and map more directly to the structure of object-oriented applications. They can scale more naturally to large data sets as they do not typically require expensive join operations. As they depend less on a rigid schema, they are more suitable to manage ad-hoc and changing data with evolving schemas.”
In terms of graph database applicability, the short answer would be: graph databases are useful for storing, traversing, and processing highly complex relationships. The expanded version:
Graph databases can help improve intelligence, predictive analytics, social network analysis, and decision and process management - which all involve highly complex relationships.
Both object databases and graph databases have been touting a lot of promises, but even if graph database scenarios abound I still think they are seen as the underdogs.
Original title and link: What Is a Graph Database? ( ©myNoSQL)