InfoWorld's top picks in the ever-expanding universe of the back-end data store The best open source databases Not so long ago, the world of open source databases could be summed up in one five-letter word: MySQL. But that was when we threw everything into a SQL database without giving it a second thought. Now we have NoSQL, horizontal scaling, and a slew of distributed key-value stores playing musical chairs around the CAP Theorem. And wait just a minute — isn’t PostgreSQL starting to look sexy? Cascading and Scalding Hadoop puts a treasure trove of data at your fingertips, but the process for extracting those riches can be daunting. Cascading provides a thin layer of Java-based data processing functionality atop Hadoop’s MapReduce execution layer. It masks the complexity of MapReduce, simplifies the programming, and speeds you on your journey toward actionable analytics. Cascading works with JVM languages like Clojure and JRuby, but we prefer Scalding, a Scala API for Cascading from Twitter. A vast improvement over native MapReduce functions or Pig UDFs, Scalding code is clean and concise. Anyone comfortable with Ruby will find the Cascading/Scala pairing a natural fit. — James R. Borck MySQL and MariaDB The most widely used open source database for Web apps (and many other things) remains MySQL. Support for multiple storage engines, clustering, full-text indexing, and plenty of other professional features have allowed numerous other apps profiled here, from WordPress to Movable Type, to rely on MySQL as their default database. Graphical front ends, such as phpMyAdmin and Adminer, make using the database far less of a chore. And for those seeking escape from the long shadow of Oracle, there’s a community fork named MariaDB, maintained by MySQL’s original lead developer, Monty Widenius. — Serdar Yegulalp Open SourceTechnology IndustryData ManagementSQL