Andy's Unix FAQ

Question;

what database uses Linux?

Answer;

I'm not entirely sure I understand your question. I think you mean "What databases are supported by Linux?"

Linux supports the three main commercial RDBMS's; Oracle, Sybase, and DB2

http://www.oracle.com/ip/deploy/database/oracle9i/index.html?db_linux.html
http://www.sybase.com/linux
http://www-3.ibm.com/software/data/db2/

You might also want to take a look at these two freely available ones.

http://www.postgresql.org
http://www.mysql.com

And dbforums offers discussion groups covering all the major databases.