Open-AudIT ships with a .sql file used to build the database schema. It is a simple matter to use this and reset the database.
NOTE - If you have changed the credentials used by Open-AudIT to access MySQL you will need to adjust the below commands.
Linux
mysql -u openaudit -popenauditpassword openaudit < /usr/local/open-audit/other/openaudit_mysql.sql
Windows
c:\xampplite\mysql\bin\mysql.exe -u openaudit -popenauditpassword openaudit < c:\xampplite\open-audit\other\openaudit_mysql.sql