How To Connect To Database

<?php
    try{
        $conn = "mysql:host=localhost;dbname=users_dbb";

        $connect = new PDO($conn,"root","");

        // set the PDO error mode to exception
        $connect->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        echo "you are connected successfully";

    }catch(PDOException $e){

        echo "Connection failed: " . $e->getMessage();

    }
?>