Example PHP and SQL application (feedback form)

A question was asked about how to log weather data to a database on a web server so that it can be accessed via the web.  https://forum.computingatschool.org.uk/t/how-to-build-an-iot-website/4699

This is a program which illustrates some of the techniques you need to do this.  It is a web app that I wrote for people to give feedback after a school visit to a local facility (which I won't name, because I don't want people filling in the live app just to see how it works).  The PHP is attached as a text file, suitably expurgated.  PS I have had to zip it to avoid the security scanner as it contains SQL statements.

The database routines are very simple -- sometimes you see much more complicated ones, but I have pared these down.  There is no need to use complicated object-oriented things.

There are some very brief instructions for making the database in the file.  The best tutorial for that is for WordPress at https://wordpress.org/support/article/creating-database-for-wordpress/.