PostgreSQL

PostgreSQL Database Server is a powerful, open source relational database system. It runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, Mac OS X, Solaris, SunOS, Tru64), BeOS, and Windows. PostgreSQL is an open-source descendant of this original Berkeley code.

If you need a PostgreSQL Database GUI, you can download NAVICAT PostgreSQL. It supports to import CSV, XML, or other formats to PostgreSQL. PostgreSQL supports a large part of the SQL: 2003 standard and offers many modern features: complex queries, foreign keys, triggers, views, transactional integrity, and multi-version concurrency control. Also, PostgreSQL can be extended by the user in many ways.