Module development and code questions

Hello, I have several modules which have configuration forms attached to them, I would like to add a submit handler to all of them before the systems_settings_form submit handler which looks at the $form_state, checks to see if any values are different to the ones currently stored in the Variables table and writes a message to Watchdog which lists the field name, the original field value, the newly submitted value and the user ID associated with the form values update.

Basically a simple module configuration settings changelog in Watchdog.

This is my first AJAX form.

I would like to know how to replace one AJAX form with an undo version of the form (for when a page element disappears).

Scenario, a tip (short piece of text) is displayed by default on certain pages to explain what that page does. It's followed by a [hide this tip] submit button.

On submit, a database action is carried out. However, on submit, I also want the tip text to be replaced with an acknowledgement "I won't see the tip on this page again" and with an [undo] submit button.

I am trying out creating a custom field module for views, but I keep getting this error when I apply the field on the view. 

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'views_report_state_field' in 'field list'

Here is my code:

FILE - views_report_state.info

name = Views Report State
description = Turns short abbreviated states (ex: TX) into fully readable names (ex: Tx = Texas)
package = Views
core = 7.x

files[] = views/views_report_state_field.inc

Hello! I'm doing content migration from JSON files (using Migrate, Migrate Plus, Migrate Tools).

I have a custom type of movie "Movie" and a taxonomy "Genre." First I import data about genres (there are no problems here), then I import the data about the films, but I can not connect the movie with certain genres (terms).

Tell me how you can do this, please.

Greetings All,

I am new to Drupal but not to php.

I am converting an older site over to D8.  One of the issues is the display of information for our site is very location specific.  It is currently handled by setting a State....ie: NJ, NY, Va, etc.  and the rest of the site gears the content of the site to that state.

I am not interested in using Geolocation as many of our users are looking for information in other places than where they currently are.

Hello,
Unfortunately, we experience problems trying to place our module on Drupal. Git repository fails to be created, so we cannot place the code there. 
https://www.drupal.org/project/elfsight_form_builder_module - this is a link to the project.