<?php

class Database
{

    private $connection;
    private static $_instance;

    private static $dbConfig = [
        'host' => 'localhost',
        'port' => 5433,
        'database' => 'vova',
        'db_user' => 'vova',
        'db_pass' => 'vova'
    ];

    private function __construct() {
        $this->connection = new PDO(
            "pgsql:dbname=" . self::$dbConfig['database'] . ";"
            . "host=" . self::$dbConfig['host'] . ";"
            . "port=" . self::$dbConfig['port'] . ";"
            . "user=" . self::$dbConfig['db_user'] . ";"
            . "password=" . self::$dbConfig['db_pass']
        );
    }

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

        return self::$_instance;
    }

    public function getConnection() {
        return $this->connection;
    }

    private function __clone() {}
}

//////////////// Use //////////////////////////////////////////////
$db = Database::getInstance(); ////////////////////////////////////
$pgsql = $db->getConnection(); ////////////////////////////////////
///////////////////////////////////////////////////////////////////
$query = "SELECT * FROM MyTable ORDER BY ID DESC LIMIT 10"; ///////
$res = $pgsql->query($query)->fetchAll(); /////////////////////////
///////////////////////////////////////////////////////////////////
print_r($res); ////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////