accessing mariadb from php Options

[Jack42]

I am writing my first publicly accessible web form that will store data in a mariadb. I have about 20 fields that the user will put their information in and then on submit. The data will go into the mariadb. The database will NOT contain social security, credit card numbers, or other sensitive information. What are some good design tips?

<?php
$dbhost = 'localhost:3036';
$dbuser = 'guest';
$dbpass = 'guest123';
$conn = mysql_connect($dbhost, $dbuser, $dbpass);

if(! $conn ) {
die('Could not connect: ' . mysql_error());
}

echo 'Connected successfully';
mysql_close($conn);
?>