To submit to SQL from a browser form, you'll have to use a web service between the form and SQL. You'll also need to do a lot of permissions work by converting that web service data connection to a Universal Data Connection using the DAta Connection Library, and you'll have to modify the contents of this UDC file to leverage a Single Sign-On entity that you make in Central Admin. That way, credentials of your users can be impersonated to the DB and passed through the double hop across servers from the browser form.
Once you do that, you basically map all your fields to the web service to tell it which fields to submit to SQL upon clicking submit.