Databases

MySQL 

An open-source Relational Database Management System(RDBMS), MySQL is the world’s most popular open source database, enabling the cost-effective delivery of reliable, high-performance and scalable web-based and rooted database applications. MySQL delivers the ease of use, scalability, and high performance, as well as a full suite of database drivers and visual tools to help developers and DBAs build and manage their business-critical MySQL applications. MySQL is developed, distributed, and supported by Oracle.

MongoDB 

A free and open-source cross-platform document oriented database program. It is classified as NoSQL database program and uses JSON-like documents with schemas. MongoDB supports field, range queries, regular expression searches. Queries can return specific fields of documents and also include user-defined Javascript functions. Queries can also be configured to return a random sample of results of a given size.