how to establish a connection with a file 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: db connection in php

Just include this Temlate in other file using PHP Include/Require Keywords
 And Make Connection In One Shot :)

<?php
  
    // echo "Welcome to Connecting of DB Tutorial!";
    // echo "<br>";

    // 1. PDO - Php Data Objects
    // 2. MySQLi extension

    // Set Connection Variable
    $server = "localhost";
    $username = "root";
    $password = "";
    $database = "test";

    // Create A Connection
    $con = mysqLi_connect($server, $username, $password, $database);

     // Check For Connection
     if(!$con){
        die ("Connection Terminated! by Die() function". mysqLi_connect_error());
       
    }
    else {
        echo "Connection Succefully Happened! <br>";
    }


    ?>