Custom Table doesn't create on plugin activation

Question

I'm a newbie in plugin development. I tried following this documentation: https://codex.wordpress.org/Function_Reference/register_activation_hook

I've created a function on the main plugin file (wp-content/plugin-folder/plugin.php). It creates the MySQL tables upon plugin activation.

CODE:

<?php
function create_db() {

 global $wpdb;

 $table_names = [
     $wpdb->prefix . "banks",
     $wpdb->prefix . "roles",
     $wpdb->prefix . "levels",
     $wpdb->prefix . "training_areas",
     $wpdb->prefix . "disciplines",
     $wpdb->prefix . "themes",
     $wpdb->prefix . "subjects",
     $wpdb->prefix . "fields",
     $wpdb->prefix . "modalities",
     $wpdb->prefix . "difficulties",
     $wpdb->prefix . "questions"
 ];

 $charset_collate = $wpdb->get_charset_collate();

 $sqls = [
     "CREATE TABLE $table_name[0](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[1](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[2](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[3](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[4](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[5](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     discipline_id INT(9) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id),
     FOREIGN KEY  (discipline_id) REFERENCES $table_name[4](id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[6](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[7](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[8](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[9](
     id INT(9) NOT NULL AUTO_INCREMENT,
     name VARCHAR(255) NOT NULL,
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id)
     ) $charset_collate;",

     "CREATE TABLE $table_name[10](
     id INT(9) NOT NULL AUTO_INCREMENT,
     code string NOT NULL,
     question VARCHAR(255)  NOT NULL,
     bank_id INT(9),
     role_id INT(9),
     level_id INT(9),
     training_area_id INT(9),
     theme_id INT(9),
     subject_id INT(9),
     field_id INT(9),
     modality_id INT(9),
     dificulty_id INT(9),
     time datetime DEFAULT '0000-00-00 00:00:00'  NOT NULL,
     PRIMARY KEY  (id),
     FOREIGN KEY  (bank_id) REFERENCES $table_name[0](id),
     FOREIGN KEY  (role_id) REFERENCES $table_name[1](id),
     FOREIGN KEY  (level_id) REFERENCES $table_name[2](id),
     FOREIGN KEY  (training_area_id) REFERENCES $table_name[3](id),
     FOREIGN KEY  (theme_id) REFERENCES $table_name[5](id),
     FOREIGN KEY  (subject_id) REFERENCES $table_name[6](id),
     FOREIGN KEY  (field_id) REFERENCES $table_name[7](id),
     FOREIGN KEY  (modality_id) REFERENCES $table_name[8](id),
     FOREIGN KEY  dificulty_id) REFERENCES $table_name[9](id),
     ) $charset_collate;"
  ];

  require_once(ABSPATH . 'wp-admin/includes/upgrade.php');

  foreach ($sqls as $sql) {
     dbDelta($sql);
  }
}

register_activation_hook(__FILE__, 'create_db');

Answer 1

Sorry Guys I've created a array $table_names and used $table_name in my sql statements.

thanks!