How do you set SQLKEY in app?

Dear Sir,

I refer to this link
https://puravidaapps.com/mysql.php

I am confuse about this line, what does it mean
Set the SQLKEY in your app and in the PHP code, they must match for this code to work
Please

Use the same sqlkey in your blocks.. in the example it would be secret

//DATABSE DETAILS//
$DB_ADDRESS="";
$DB_USER="";
$DB_PASS="";
$DB_NAME="";

//SETTINGS//
//This code is something you set in the APP so random people cant use it.
$SQLKEY="secret";

Taifun

Sir Taifun
You mean I should create my connection file like this one

<?php

$servername = "localhost";
$username = "id2064928298_hussain"; 
$password = "Tariq******678";//mod edit
$database = "id2064928298_asiacafe";
$SQLKEY="secret";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $database);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

echo "Connected successfully";
?>

Yes you can try this...
Let us know if it works
Taifun
PS: personally I would not post my server password in a public community...

Sir the user name and password that I uploaded is fake