Переезд с Mysql на Mysqli

<?php 
	global $config; 
	include_once("config.php"); 
	$config["show_error"] = false; 
	$config["encode_key"] = "KEY"; 
	$config["table_settings"] = "settings"; 
	$config["table_users"] = "users"; 
	$config["table_types"] = "types"; 
	$config["table_categorys"] = "category"; 
 
	function db_connection() 
	{ 
		$data_sql = mysqli_connect($config["sql_host"], $config["sql_user"], $config["sql_pass"], $config["db_name"]); 
		mysqli_query($data_sql, "SET NAMES utf8"); 
	} 
	function db_close() 
	{ 
		global $data_sql; 
		@mysqli_close($data_sql); 
	} 
	function clean($str) 
	{ 
		$str = @trim($str); 
		if(get_magic_quotes_gpc()) 
		{ 
			$str = stripslashes($str); 
		} 
		return mysqli_real_escape_string($str); 
	} 
	function is_login() 
	{ 
 
		if (isset($_SESSION['userId']) && ($_SESSION['username']) && ($_SESSION['regDate'])) 
		{ 
			return true; 
		} 
		else 
		{ 
			@session_destroy(); 
			return false; 
		} 
	} 
    function is_login_seller() 
	{ 
 
		if (isset($_SESSION['userId']) && ($_SESSION['username']) && ($_SESSION['regDate']) && ($_SESSION['userType'] == '3')) 
		{ 
			return true; 
		} 
		else 
		{ 
			@session_destroy(); 
			return false; 
		} 
	} 
	function is_login_admin() 
	{ 
 
		if (isset($_SESSION['userId']) && ($_SESSION['username']) && ($_SESSION['regDate']) && ($_SESSION['userType'] == '1')) 
		{ 
			return true; 
		} 
		else 
		{ 
			@session_destroy(); 
			return false; 
		} 
	} 
function sql_error() 
{ 
	if ($config['show_error']) 
	{ 
		die('Invalid query: ' . mysqli_error($data_sql)); 
	} 
	else 
	{ 
		die("Error, please contact webmaster for more information."); 
	} 
} 
 
	if (!$config['show_error']) 
	{ 
		error_reporting(1); 
	} 
	session_start(); 
 
	db_connection(); 
	$sql = "SELECT * FROM " . $config["table_settings"]; 
	$result = mysqli_query($data_sql,$sql); 
	if ($result) 
	{ 
		while ($setting = mysqli_fetch_assoc($result)) 
		{ 
			$listSetting[] = $setting; 
		} 
		if (is_array($listSetting)) 
		{ 
			foreach($listSetting as $setting) 
			{ 
				$config[$setting[settingName]] = $setting[settingValue]; 
			} 
		} 
		else 
		{ 
			die("Data setting has error."); 
		} 
	} 
	else 
	{ 
		if ($config['show_error']) 
		{ 
			die('Invalid query: ' . mysqli_error($data_sql)); 
		} 
		else 
		{ 
			die("Error, please contact."); 
		} 
	} 
	db_close(); 
?>