PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
MySQL - The world's most popular open source database
SQLite - SQLite Home Page
Microsoft SQL - Microsoft SQL is a best in class relational database management software that facilitates the database server to provide you a primary function to store and retrieve data.
MariaDB - An enhanced, drop-in replacement for MySQL
SAP HANA - SAP HANA is an in-memory, column-oriented, relational database management system.