Tom,
First off, BEAUTIFULLY implemented script!

Is there a way to display the content of the database without having to enter a username / password. And consequently not have the ability to delete / edit the database?

WORKFLOW: Site owner would enter content into the database via the form, and edit the database via a username/pass. A visitor would not have to enter a username/pass but would be able to search & view the records.

You can copy the staff folder and rename it to guest or something.
Keep the staff folder for the administration. Remove the login page from
the guest folder to show the data to guests.