Use the mail function. Simply add the functionality to send an email after you made the update statement.

Once you post the data, insert it into the mysql database, use the mail function to send the confirmation through the email. Usually mail function does not work on local systems as no mail exchange service is installed like SMTP. So u need to test it on a real-time hosting server.

Refer the mail function documentation here -> http://php.net/mail

You could use something like PageGate with the commandline/ascii to send alert when a record or something is updated. Does not have to be an email could be a text message as well.
HTH