NoSQL databases are database engines that use various non-relational methods to store, retrieve, and manage data. There are a variety of data models being employed in the NoSQL space including the most common: key-value store, document store, and wide column store. By utilizing these data models, NoSQL databases, if applied to the right applications, provide many advantages over the traditional relational model. Some of the notable advantages of a great NoSQL database include:
- Scalability – Great NoSQL databases are built with scalability in mind, allowing for easy scaling for dealing with large, growing data needs.
- Availability – A good NoSQL database is architectured to provide maximum and continuous availability.
- Flexibility – Whether working with non-structure, semi-structure, or structured data, most NoSQL databases are schema-less and can easily be modified as your needs change.
- Efficiency – In addition to being lightweight, NoSQL databases are created for fast and efficient data storage and retrieval.
The popularity of NoSQL databases can be attributed to the rise of modern web-based applications and the need to work with the massive amount of data associated with them. Currently, there are hundreds of open source NoSQL databases available to choose from, but in this article, we will explore the top 3 NoSQL databases: MongoDB, Cassandra, and Redis. According to Google Trends (see below), these NoSQL databases has been rapidly growing in popularity over the past few years. As web applications evolve and require bigger data, the use of NoSQL databases will become critical to the success of web/cloud based products or businesses.
MongoDB is currently the most popular and widely used NoSQL database. This general purpose database has been used by many large companies such as Facebook, eBay, Forbes, and many others. MongoDB implements a document store data model which stores data in BSON documents similar to JSON files. Features of MongoDB include:
- Easily scalable
- Powerful document-based query language
- Fast processing
- Load balancing
- Schema-less design
- High availability
- Simple database administration
- Replication and sharding
Apache Casandra is another very popular and proven NoSQL database employed by the likes of Instagram, Netflix, and Apple. The combination of the wide column store data model and emphasis on performance makes Apache Cassandra one of the fastest NoSQL database available. Some great benefits of Apache Cassandra are:
- Automatic replication
- Continuous(100%) availability
- High performance
- Highly scalable
- Flexible Data Model
- Large Developer/Support Community
By far the most popular key-value store database, Redis uniquely uses in-memory datastore for super fast performance and very low latency. Some of the most notable benefits and features of Redis are:
- High performance/ low latency
- Simple asynchronous replication
- Different persistence/durability options
- Lua scripting
- Pub/sub support
- Multiple programming language support