Totally agree. I was more using "relational" to mean "cross-relational". I.e. Consider plotting your data on a 2-dimensional space, connecting your "related" da

Totally agree. I was more using "relational" to mean "cross-relational". I.e. Consider plotting your data on a 2-dimensional space, connecting your "related" data with lines. If your data looks like a spiderweb, probably some graph-type database is most appropriate. If your data resembles an inverted funnel (hierarchical) more than a spiderweb, then a document-store probably is more appropriate. More traditional relational databases are probably more appropriate somewhere in between (which is probably why they're still the most popular type of database being used). Of course, I can't think of any real-world scenario where your data wouldn't resemble a bit of both. Even very hierarchical data usually has some cross-relationships between un-nested documents, which is why it's still awesome to have a document-store database that supports join-type relationships.