<?php
$servername = "db";
$username = "root";
$password = "example";
$db="frise";

// Create connection
$sql = new mysqli($servername, $username, $password);

// Check connection
if ($sql->connect_error) {
  die("Connection failed: " . $sql->connect_error);
}
$sql->select_db($db);
echo "Connected successfully";
?>