How can I prevent database being written to again when the browser does a reload/back?

Question

I\'m putting together a small web app that writes to a database (Perl CGI & MySQL). The CGI script takes some info from a form and writes it to a database. I notice, h

Answer 1

Using a POST request will cause the browser to try to prevent the user from submitting the same request again, but I'd recommend using session-based transaction tracking of some kind so that if the user ignores the warnings from the browser and resubmits his query your application will prevent duplication of changes to the database. You could include a hidden input in the submission form with value set to a crypto hash and record that hash if the request is submitted and processed without error.