Query String to Mysql

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

$now = new DateTime();
parse_str( html_entity_decode( $_SERVER['QUERY_STRING']) , $out);

if ( array_key_exists( 'heap' , $out ) ) {
  // Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$datenow = $now->format('Y-m-d H:i:s');
$hvalue  = $out['heap'];

$sql = "INSERT INTO HeapTable ( datelog , heapvalue) VALUES ( $datenow , $hvalue )";

if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
}
?>