<?php

class DB
{
	private static $_instance = null;

	// для безопасности настройки лучше хранить в файле с конфигом
	private static DB_HOST = '';
	private static DB_NAME = '';
	private static DB_USER = '';
	private static DB_PASS = '';

	private function __construct () {

		$this->_instance = new PDO(
			'mysql:host=' . self::DB_HOST . ';dbname=' . self::DB_NAME,
	    	self::DB_USER,
	    	self::DB_PASS,
	    	[PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"]
	    );

	}

	private function __clone () {}
	private function __wakeup () {}

	public static function getInstance()
	{
		if (self::$_instance != null) {
			return self::$_instance;
		}

		return new self;
	}
}