alt Hacker NewsA few months back I decided to write an embedded db for my firm's internal JS framework. Learned a lot about how/why databases work the way they do. I use stuff like reading memory cached markdown files for static sites, but there are certain things that a database gives you (chief of which for me was query ergonomics—I loved MongoDB's query language but grew too frustrated with the actual runtime) that you'll miss once you move past a trivial data set.
I think a better way to ask this question is "does this application and its constraints necessitate a database? And if so, which database is the correct tool for this context?"
For me, I just wish MongoDB had scaling options closer to how Elatic/Cassandra and other horizontally scalable databases work, in that the data is sharded in a circle with redundancy metrics... as opposed to Mongo, which afaik is still limited to either sharding or replication (or layers of them). FWIW, I wish that RethinkDB had seen more attention and success and for that matter might be more included to use CockroachDB over Mongo, where I can get some of the scaling features while still being able to have some level of structured data.