$host = "localhost";
$db = "mydb";
$user = "user";
$pass = "qRES2fIWK8Gg";

try
{
    $db = new PDO("mysql:host = $host; dbname = $db", $user, $pass);
    $db -> exec ("SET NAMES utf8"); // charset = utf8 doesn't work.
    echo "Database connection is successful. <br>";
}

catch (PDOException $e)
{
    echo $e -> getMessage();
}

SELECT * FROM settings WHERE settings_id= :id

SELECT * FROM mydb.settings WHERE settings_id= :id

"mysql:host=$host;dbname=$db"