<?php

//Check for mysql connection
if (!mysql_connect("host","user","pass"))
  die('Could not connect: ' . mysql_error());

//Escape SQL characters to protect against SQL injection
$username = mysql_real_escape_string($_POST['username']);
$hostname = mysql_real_escape_string($_POST['hostname']);
$ip = mysql_real_escape_string($_POST['ip']);
$email = mysql_real_escape_string($_POST['email']);

mysql_select_db("database");

//Query to check for username match
$userCheck = "SELECT * FROM `Accounts` WHERE username = '$username'";

if(mysql_num_rows(mysql_query($userCheck)) != 0)
    die("Sorry, username is already in use. Please go back and try again.");

//If the username isn't found, insert the values
$sql = "INSERT INTO Accounts VALUES ('$username','$hostname','$ip','$email')";

if (mysql_query($sql)) {
    //Successful query
    header ("location: /done.html");
    exit();
} else
    //Failed query
    die("Something is wrong, we could not complete your request.");
?>