connect or not connect in php code example

Example 1: php sql connection

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// Create connection
$conn= mysqli_connect($servername,$username,$password,$dbname);
// Check connection
if (!$conn) {
  die("Connection failed: " . mysqli_connect_error());
}
echo "Connected Successfully.";
?>

Example 2: $conn php

<?php
    $user = "username";
    $pass = "password";
    $host = "host";
    $dbdb = "database";
    
$conn = new mysqli($host, $user, $pass, $dbdb);
   if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
?>