MySQL

vs

IBM DB2

PostgreSQL, or Postgres for short is a widely popular, free and open-source relational database management system. PostgreSQL is available for all major operating systems including macOS, Linux, Windows, BSD and Solaris. The project has been in active development for over 30 years now, and powers many of the applications you use on a daily basis.

MariaDB is an free and open-source, community-developed relational database management system. MariaDB is a fork of MySQL, and is developed and maintained by the creators of MySQL, after concerns over its acquisition by Oracle Corporation in 2009. The databases comes bundled by default with most Linux distributions and is also apart of most cloud offerings. MariaDB is built upon the values of performance, stability, and openness which is ensured through the MariaDB Foundation.

MongoDB is an open-source document-oriented distributed database built for modern applications. MongoDB uses JSON-like documents with optional schemas and is classified as a NoSQL database. The database is freely distributed under the Server Side Public License, but MongoDB provides commercial version of the database for enterprise-scale applications.

RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.

BigchainDB allows developers and enterprise to deploy blockchain proof-of-concepts, platforms and applications with a blockchain database, supporting a wide range of industries and use cases. BigchainDB provides high throughput, low latency, powerful query functionality, decentralized control, immutable data storage and built-in asset support, BigchainDB is like a database with blockchain characteristics.

NuoDB is a distributed relational database management system utilizing SQL. The database is architected to meet the rapidly evolving demands of today's enterprises, NuoDB can be used to deploy on-premise, extend to the cloud, scale on demand, eliminate downtime and reduce total cost of ownership. All while maintaining SQL compatibility and a workflow that most developers are familiar with.