[seldo]

You make a very valid point, and it's one I do think about. I try not to bash NoSQL, because it does make sense sometimes, but there's a recent tide of "SQL is dead, long live NoSQL" that ignores the fact that RDBMS are a superior solution in some cases. Really, I think most people agree that RDBMS are sometimes better, and the argument revolves around how often "sometimes" is.

I don't doubt that NoSQL systems solve scalability problems people experience when they use (or rather, mis-use) RDBMS. My point is that they are making trade-offs in terms of storage, data integrity, etc. that they may not be considering, because those things used to be "free" with RDBMS so they weren't a concern.

It's certainly true that RDBMS were born in a very different age in terms of expense of both storage and processing. As with MapReduce, with is an astonishingly inefficient but extremely fast and scalable way of crunching big volumes of data, NoSQL systems may be making use of huge leaps in the availability of resources to prioritize speed and scalability over other concerns.

However, as I mentioned, there seem to be lot of newbie developers who aren't thinking about NoSQL vs. RDBMS in these terms ("speed" vs. "data integrity", say) but instead in terms of "easy" vs. "hard", or even just "new hotness" vs. "old and busted". As a result they may be avoiding one set of problems solved by NoSQL only to run into a totally different set solved by RDBMS, without considering which is more important for their app.