[threeseed]

That's because you took my examples and distorted them.

I specifically mentioned MongoDB and MySQL. Having a JSON type is basically a mini document database since it uses a different/enhanced query language and is often not relational with the rest of the schema.

I also specifically mentioned MongoDB and Neo4J. Yes you could implement a graph in MySQL but as your paper lists you will need to front it with a Memcache in order to cache the graph traversal lookups. With a graph database you generally don't need such a cache.