There are also SQL based non-relational, non-acid, non (strictly speaking) database systems too, particularly for OLAP uses. Hive (and in the most recent versio

There are also SQL based non-relational, non-acid, non (strictly speaking) database systems too, particularly for OLAP uses. Hive (and in the most recent versions/through a plugin, Pig too) provides SQL support on top of Hadoop. While that's somewhat of a misplaced fit (SQL is based on relational algebra, why use relational algebra on a non-relational store?), it does provide a convenient interface for ad-hoc querying, particularly for non-engineers (e.g. business analysts). Edit: addendum - Honestly, my own personal preference would be with either a language specifically designed for the non-relational store in question (e.g. Pig Latin) or a DSL in a general purpose programming language (e.g. Cascading or especially Clojure-based macros the Flightcaster team has created on top of Cascading).