wiratama

@echo off

REM move into the backups directory
CD C:\backup

REM Create a file name for the database output which contains the date and time. Replace any characters which might cause an issue.
set filename=database %date% %time%
set filename=%filename:/=-%
set filename=%filename: =__%
set filename=%filename:.=_%

wiratama

Creating custom table in drupal 8 is not recommended. Create entity types instead.  
But if you want to Create custom table you can create either by implementing hook_schema or 
else create schema file config/schema/your_custom_module_name.schema.yml  in your module 
(https://www.drupal.org/docs/8/api/configuration-api/configuration-schemametadata). 

( https://drupal.stackexchange.com/questions/219580/best-practice-for-creating-table-in-custom-module  )

1. Implementing  hook_schema in .module file (Not recommended).

/**

wiratama

<?php
/**
 * @file
 * Contains \Drupal\jcmodule\Theme\ThemeNegotiator
 */
namespace Drupal\jcmodule\Theme;

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Theme\ThemeNegotiatorInterface;