Its been a while since I enjoyed my adventures with CouchDB. I sure wish I could have some extra time to pick this up again, but getting some sleep at night is nice too once in a while. I noticed that OO databases and document/key-value stores are getting more and more traction lately and I must say that its about time.
Put as gently as I can – relational systems are an answer to a problem that we faced 30 years ago. What you’re doing now is nothing other than compensating for a lack of imagination from the platform developers. Think about it – we code using Object Oriented approaches, we store those objects in a relational system.
What we should all learn in this industry is to stop assuming that a relational database is the default option for storing the data of every solution we build. This is what we have been doing for a long time and its pure madness, plain and simple.
RDBMS don’t fit for holding your application’s data, and they don’t fit for reporting. They’re a solution for a problem that doesn’t exist anymore. Time to kick them to the curb.
The most typical setup you see is a single relational database that is used for both storing the data of an application as well as reporting from this data. The relational schema usually sits between normalized and denormalized tables, which means having a compromise for both needs. You can get away with this for small to medium-sized applications, but when you start working on mission-critical solutions with higher volumes, this compromise isn’t going to cut it anymore. This is why Greg Young, Udi Dahan and Mark Nijhof amongst others are advocating command query separation. For these kind of solutions, you want to have the best option for handling commands, which could be an OO database or a document/key-value store (with or without event-sourcing) and for reporting you’d want the best option available as well like an OLAP system. What I’m describing here is just the elevator pitch, so if you want to learn more about this then do check out the resources that these gentlemen mentioned above have already put on their blogs.
I hope that one day we realize that a relational database was just a means for optimizing file storage, which is hardly a need anymore these days. We shouldn’t be struggling with how to solve the impedance mismatch between relational databases and OO programming in any kind of application. The one thing we should care about is how to provide solid and clean solutions to our businesses without having to worry about tables and those zealots with their holy database schemas. Just store the objects you want and worry about other things like the so-called ‘ilities’ and being able to respond to business needs in a timely manner.