CUBRID is an open-source relational DBMS that is designed for on-line web applications.
Relational
http://www.cubrid.org/
https://github.com/CUBRID/cubrid
https://www.cubrid.org/documentation/manuals
Naver Corporation
KR
2008
Commercial, Open Source
C
MySQL
Linux, Windows
GPL v2
https://en.wikipedia.org/wiki/CUBRID