Update database and helper functionality in CodeIgniter

Revised database drivers, query builder, and file/inflector helpers for improved consistency and functionality. Updated copyrights, links, and standardized function names including deprecating `is_countable` in favor of `word_is_countable`. Added support for new SQL features and optimized query handling.

system/database/drivers/sqlite3/sqlite3_driver.php

@@ -6,7 +6,7 @@
  *
  * This content is released under the MIT License (MIT)
  *
- * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ * Copyright (c) 2019 - 2022, CodeIgniter Foundation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -29,8 +29,9 @@
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
- * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
- * @license	http://opensource.org/licenses/MIT	MIT License
+ * @copyright	Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
+ * @copyright	Copyright (c) 2019 - 2022, CodeIgniter Foundation (https://codeigniter.com/)
+ * @license	https://opensource.org/licenses/MIT	MIT License
  * @link	https://codeigniter.com
  * @since	Version 3.0.0
  * @filesource
@@ -48,7 +49,7 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  * @subpackage	Drivers
  * @category	Database
  * @author		Andrey Andreev
- * @link		https://codeigniter.com/user_guide/database/
+ * @link		https://codeigniter.com/userguide3/database/
  */
 class CI_DB_sqlite3_driver extends CI_DB {
 
@@ -230,24 +231,18 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 */
 	public function list_fields($table)
 	{
-		// Is there a cached result?
-		if (isset($this->data_cache['field_names'][$table]))
-		{
-			return $this->data_cache['field_names'][$table];
-		}
-
 		if (($result = $this->query('PRAGMA TABLE_INFO('.$this->protect_identifiers($table, TRUE, NULL, FALSE).')')) === FALSE)
 		{
 			return FALSE;
 		}
 
-		$this->data_cache['field_names'][$table] = array();
+		$fields = array();
 		foreach ($result->result_array() as $row)
 		{
-			$this->data_cache['field_names'][$table][] = $row['name'];
+			$fields[] = $row['name'];
 		}
 
-		return $this->data_cache['field_names'][$table];
+		return $fields;
 	}
 
 	// --------------------------------------------------------------------