Librería BSD para almacenar en base de datos una estructura de grafo, de forma eficiente. Free software.
The e4Graph library enables your program to represent and manipulate graph-like data efficiently and to store this data persistently. The overhead for persistence is etremely low, so e4Graph is useful also for when you do not care about keeping the data around between runs of your program; you can use it purely as a data structure library, without concern for persistence.
The key benefit provided by e4Graph is that it frees you to think about your data structures and the relations between the various entities without worrying about how to build the data structure and how to efficiently store it. Your program accesses and manipulates the data according to the relationships it represents, and e4Graph takes care of how to represent the data efficiently and persistently. Data is loaded into the executing program on demand, as a connection from an already loaded item to an on-disk item is followed; this data loading step is transparent to your program, and in-memory storage is recovered automatically when the data is no longer accessible by your program. This allows e4Graph to efficiently manipulate data graphs whose sizes are several orders of magnitude larger than the machine's available memory.