Why NoSQL?

Today, three interrelated megatrends – Big Data, Big Users, and Cloud Computing – are driving the adoption of NoSQL technology. More and more organizations recognize that operating at scale is better achieved on clusters of standard, commodity servers, and a schema-less data model is often better for the variety and type of data captured and processed today.

Features of NoSQL:

• Simplicity of design
• Horizontal scaling
• Finer control over availability
• No schema
• Support structures: key/value, graph...
• Embedded documents and arrays reduce need for joins as in relational SQL, which is key for high performance and speed.

Developers want a very flexible database that easily accommodates new data types and isn’t disrupted by content structure changes from third-party data providers. Much of the new data is unstructured and semi-structured, so developers also need a database that is capable of efficiently storing it. 

A NoSQL database is the type of database that can handle the sort of unstructured, messy and unpredictable data that our system of engagement requires.

For example, a document-oriented NoSQL database takes the data you want to store and aggregates it into documents using the JSON format. Each JSON document can be thought of as an object to be used by your application. A JSON document might, for example, take all the data stored in a row that spans 20 tables of a relational database and aggregate it into a single document/object. Aggregating this information may lead to duplication of  information, but since storage is no longer cost prohibitive, the resulting data model flexibility, ease of efficiently distributing the resulting documents and read and write performance improvements make it an easy trade-off for web-based applications.

NoSQL is not built on tables and does not employ SQL to manipulate data. It also may not provide full ACID (atomicity, consistency, isolation, durability) guarantees, but still has a distributed and fault tolerant architecture. The NoSQL taxonomy supports key-value stores (dictionary structure), document store, BigTable, and graph databases. Redis is one of the most popular key-value store.

NoSQL is gaining momentum, and is supported by Hadoop, MongoDB, DynamoDB (Amazon Service) and others.

Reference: 

• http://www.couchbase.com/why-nosql/nosql-database
• http://www.zdnet.com/what-is-nosql-and-why-do-you-need-it-7000004989/