[emin_gun_sirer]

Absolutely spot on. But there is no reason why the translation from the user's query into a series of data accesses cannot happen in the front end. In many ways, NoSQL is a reaction to the poor job RDBMSs were doing in the front end. Everyone has seen the cases where AWK programs on desktops could outperform expensive Oracle servers, and that's mostly because they enable the user to put to use what they know of their specific data and their access patterns.

So, in between "writing a program for each query" (which I agree is a non-starter in some settings) and "SQL is the one and only interface" lies an exciting space of opportunities.