Very interesting post on the Shopify Engineering Blog on the difference between 5 types of data-stores available to developers, and under what circumstances they should be used.

I find it tricky to decide on the best technology for storing data for a particular project. I guess the important thing to keep in mind is to try and figure out as best you can how the data is going to be used (i.e. queried). If you know that, the decision should be easy once you know what’s out there, and this blog post certainly helps in this regard. If you don’t, I guess the next best thing is to try to find the option that will give you the most flexibility with hopefully not too much loss in performance.