updation of table through php mysql - php

Question

This is my code to update a table. My problem is that after submitting a fresh record I'm unable to update the first time (it shows blank), but the second time it works fine.
One more thing: when I remove the include statement then it is working fine on submessage.php there is no any phpcode. [annakata: I have no idea what this means]
$pid = $_GET['id'];
$title = $_POST['title'];
$summary = $_POST['summary'];
$content = $_POST['content'];
$catid = $_POST['cid'];
$author = $_POST['author'];
$keyword = $_POST['keyword'];
$result1= mysql_query("update listing set catid='$catid',title='$title',
summary='$summary',content='$content', author='$author', keyword='$keyword' where pid='$pid'",$db);
include("submessage.php");

Answer 1

The things that are wrong with that piece of code are hard to enumerate. However, at the very least, you should establish a connection to the database before you can query it.

Answer 2

Why not just redirect to submessage.php rather than inlining it? Redirecting also prevents duplicate db operations when user refreshed the page. Just replace include statement with:
header('Location: submessage.php?id=' . $pid);
die();
Also, before you deploy your application: DO NOT EVER PUT USER INPUT DIRECTLY IN SQL QUERY. You should used bound parameters instead. Otherwise, you could just as well publicly advertise your database admin password. Read more on PDO and prepared statements at http://ie.php.net/pdo
Here's how I would do it:
$pdo = new PDO(....); // some configuration parameters needed
$sql = "
UPDATE listing SET
catid=:catid, title=:title, summary=:summary,
content=:content, author=:author, keyword=:keyword
WHERE pid=:pid
";
$stmt = $pdo->prepare($sql);
$stmt->bindValue('catid', $_POST['catid']);
$stmt->bindValue('title', $_POST['title']);
$stmt->bindValue('summary', $_POST['summary']);
$stmt->bindValue('content', $_POST['content']);
$stmt->bindValue('author', $_POST['author']);
$stmt->bindValue('keyword', $_POST['keyword']);
$stmt->bindValue('pid', $pid = $_GET['id']);
$stmt->execute();
header('Location: submessage.php?id=' . $pid);
die();
Or in fact, I would use some ORM solution to make it look more like that:
$listing = Listing::getById($pid = $_GET['id']);
$listing->populate($_POST);
$listing->save();
header('Location: submessage.php?id=' . $pid);
die();

Answer 3

Other than the usual warnings of SQL injection - very likely given your code and where you're obtaining the query parameters from (sans any kind of validation) - then it's quite possible your problem has nothing to do with the queries, particularly if it's working on subsequent attempts. Are you sure $_GET['id'] is set the first time you call the script?
Just to note, there is absolutely no reason to have to perform several update queries for each field you need to update - just combine them into a single query.