Feature: Cloud Computing

T he exponential growth of the Internet has resulted in an explosion of data sources, creating storage and data-usability problems. Furthermore, an increase in the number of data types has created challenges in terms of storing and manipulating unstructured data. These issues have lead companies and open source communities to build new tools, known as NoSQL systems or “key-value-store” systems, which aim to offer, on a massive scale, ondemand services and simplified application development and deployment. NoSQL databases are useful for applications that deal with very large semistructured and unstructured data. The growing popularity of big data will compel many companies to use NoSQL databases1 instead of traditional database, so you can expect to see vendors offering simplified rollouts and additional support for NoSQL solutions.2 According to nosql-database.org, there are at least 150 NoSQL databases, with various features to meet the requirements of different user groups. It’s not possible to discuss all of them here, so I selected 15 popular NoSQL databases that are representative (rather than inclusive), and I review some of their interesting characteristics.