如何保持提交的URL ID？

Question

When I click submit, the data is submitted to the database but the URL id of the book disappears to ----book.php

I want the URL to go back to the id of the page e.g. ----book.php?id=3

Is it possible to keep the first line as action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" and add the value="<?php echo $book_id ?>"?

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <input type="hidden" value="<?php echo $book_id ?>" name="book_id" />
    <p>Author: <input type="text" value="<?php echo $_SESSION['author']; ?>" name="author" id="author" readonly /></p>
    <p>Summary: <input type="text" name="summary" value="<?php echo $summary;?>" /></p>
    <p><input type="submit" name="submit" value="Submit" /></p>
    <input type="hidden" name="submitted" value="TRUE" />    
</form>

PHP code:

if (isset($_GET['id'])) {
    $book_id = $_GET['id'];
}

Answer 1

Please try this code:

// save values in DB

header('Location: book.php?id=' . $book_id);
exit;