Great article by Sarah Mei explaining when and how using a document model can lead to complex application code and bad performance. " When you’re picking a data store, the most important thing to understand is where in your data — and where in its connections — the business value lies. If you don’t know yet, which is perfectly reasonable, then choose something that won’t paint you into a corner. Pushing arbitrary JSON into your database sounds flexible, but true flexibility is easily adding the features your business needs. " Why You Should Never Use MongoDB: http://www.sarahmei.com/blog/2013/11/11/why-you-should-never-use-mongodb/