I guess I am old-school but you are listing a bunch of reasons why MongoDB is not evil, yet each and every one of these reasons turns out to be extremely risky

I guess I am old-school but you are listing a bunch of reasons why MongoDB is not evil, yet each and every one of these reasons turns out to be extremely risky business. All of which simply do not apply with relational datastores. The thing I took away from your post is that had you used a 20-year-old relational datastore you would have 0 of your issues anyway. > The advantages of schemaless documents are priceless. Not having to migrate is just one of the perks. Our schemas were largely in the form of Orders (having many) Shipments (going_from) ShipPoint (to) ShipPoint You say priceless. I don't think it means what you think it means. A migration is costly but also pretty rare. I migrate PostgreSQL with 100k+ rows as a matter of routine, it's over before you know it. The schema you are using (orders have many shipments going from point to point) are easily expressed in a relational schema and once defined would hardly ever need to change, if at all during the lifetime of the application. So what if I need to add a column here or there. It won't matter at all. Do you have more than 100 million documents in MongoDB? I guess you don't. Even if you do, relational has that covered too. > This doesn’t always have to be the case, though it significantly contributes to Mongodb’s fast writes. What you are saying is that I need to change MongoDB in order to make it safe. Relational database are safe out of the box, no change necessary. > We add a lot of Notes to each shipment [...] it doesn’t critically affect the business workflows of the application. Say what? You're fine with data, even notes, being lost? That is completely acceptable to you? I guess this is what shocks me most. You kids think it's normal to lose data, and consider storing a note to be optional or something. It baffles me. If a note is optional, why have it in the first place? > They do but since most of the stuff is memory mapped Translates to: you need to have your data in RAM. This does not scale at all. It doesn't even begin to scale to the level where MySQL was. TEN years ago. > Here is a simplified snapshot What follows is a class that is 236 lines long. Two hundred and thirty-six lines long. Dear sir, if this is your simplified code I fear what your actual production code looks like. If you committed that to one of my repos we would have a very serious talk. Also you would do this exactly once during your career at my company. > I haven’t even touched upon the replication and sharding features that Mongodb offers which I will reserve for another post. Which every relational store also offers. > To summarise I feel Mongodb is awesome Why is it awesome? You have only shown me why it is horrible. I have seen nothing that is awesome. Optional data persistence, needs huge amounts of RAM, complex application level code to deal with reports, this is all stuff that you can do better, faster and more reliable with a relational solution.