> One downside of both hierarchical and network (graph) models that is not mentioned either in the post or parent comment is, "access path dependence". Network

> One downside of both hierarchical and network (graph) models that is not mentioned either in the post or parent comment is, "access path dependence". Network model allows multiple paths but basically just forestalls the issue. Yes. I think that this access path independence is an essential part of the relational query approach, (of which SQL is one example), being high-level. And once you have such a language, query optimization becomes essential.