A graph database basically caches related entities with the root entity, so lookups are fast when the query follows the paths of the graph. The price is that an

A graph database basically caches related entities with the root entity, so lookups are fast when the query follows the paths of the graph. The price is that any other query is extremely costly. But if it works for your use case, more power to you. But not really relevant in a discussion about ORMs - Object Relational Mappers. The relational model was designed to address the limitations of the network/graph database, especially to allow arbitrary (ad-hoc) querying and to decouple the physical storage from the logical model. But if you don't need all that, a graph database may be fine.