MySQL

MySQL Pronounced "my S-Q-L" or "my-see-quill," it is a very popular open source, Relational DBMS from MySQL AB, Uppsala, Sweden (www.mysql.com) that runs under various versions of Unix, Windows and Mac.
Widely used for Web applications and Embedded applications,MySQL is available for free from MySQL AB under the GNUlicense as well as for a fee without restrictions. MySQL includes a C/C++ interface.
There are also ODBC and JDBC drivers available, and many scripting languages such as Perl, Python, TCL, etc. support it.