NoSQL Database Phenomenon

The chapter explains that NoSQL databases emerged as an attempt for resolving the limitations of relational databases in coping with Big Data. The issue of Big Data is related to extensive requests for the storage and management of complex, dynamic, evolving, distributed, and heterogeneous data from different sources and platforms. The chapter provides an overview of the technologies, including Google File System (GFS), MapReduce, Hadoop, and Hadoop Distributed File System (HDFS), which were the first responses to Big Data challenges and main driving forces for the development of NoSQL databases. Also, the chapter asserts that NoSQL is an umbrella term related to numerous databases with different architectures and purposes, which can be classified in four basic categories: key-value, column-family, document, and graph stores. The chapter discusses the general features of NoSQL databases, as well as the specific features of each of the four basic categories of NoSQL databases.