By purging, do you mean you want to remove all the data, or that you wish to delete the database completely?
If you want to delete it, just right click within Enterprise Manager, and select "delete".
If you are wanting to remove all the data, you will need to issue a "TRUNCATE" statement on each of the tables, keeping in mind primary/foreign key relationships. If you are going to be doing this regularly, I would suggest that when you get all the data out, take a backup. Then, in the future, when you wish to clear it out, just restore that backup.
Steve