<?php
$servername ='localhost';
$username = 'root';
$password = '12345';
$dbname = 'test';
try {
   $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
   $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
   do stuff ...
}
catch(PDOException $e) {
   echo $e->getMessage();
}

class Database {
    // DB Params
    private $host = 'localhost';
    private $db_name = "test";
    private $username = "root";
    private $password = "12345";
    private $conn;

    // DB Connect
    public function connect() {
        $this->conn = null;
        echo "connect() - ";
        try {
            $this->conn = new PDO('myqsl:host=' . $this->host . ';dbname=' . $this->db_name, $this->username, $this->password);
            $this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);


        } catch(PDOException $e) {
            echo 'HEY! Connection Error: ' . $e->getMessage();
        }

        return $this->conn;
    }
}