I have a WordPress site that I need to place some forms on that when submitted the form data is updated in an external MySql database of an in-house business system.
Obviously you could customize the PHP form handler of whichever form plugin you choose, but I would imagine in most cases this is not plugin ‘upgrade safe’
The other option would be do develop the form (and handler) outside WordPress and include it in an iFrame on a WordPress page. This is a clunky solution though in my opinion as I think iFrames should be avoided whenever possible.
IDEALLY, there’s a really robust form plugin out there that has taken these things into consideration and allows modular update of external databases by specifying database credentials and what form fields you want to map to which tables and fields. Or at the least provide an option of an include file for any custom post processing of the form data that is upgrade safe.
What are the best options?