Passing variables across pages

[simiking]

Hi all,
I'm having problems passing my variables using thru the url. Here's the code.

$connection = mysql_connect($dbhost, $dbusername, $dbpassword) or die (mysql_error());
		mysql_select_db($dbname, $connection);

//i use this line to test that variable id has been passed. 
 //this also happens to be the error point
		$test = "select * from jobpost where id=".$_GET['id'];
		echo $test;
		$run = mysql_query($test) or die(mysql_error());
		$row = mysql_fetch_assoc($run);
		
 		if ($_SERVER['REQUEST_METHOD'] == 'GET'){
	  ?>
<form method="post" enctype="application/x-www-form-urlencoded" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<fieldset>
<legend>Edit Vacancy</legend>
    <label for="jobtitle">Job Title</label>
   	<input type="text" name="jobtitle"  value="<?php echo htmlentities($row['jobtitle']); ?>"/><br />
        
    <label for="jobdescription">Job Desription</label>
    <textarea name="jobdescription" cols="50" rows="10" ><?php echo strip_tags( nl2br (($row['jobdescription']))); ?></textarea><br />
         
   <label for="jobqualifications">Job Qualifications</label>
    <textarea name="jobqualifications" cols="50" rows="10" ><?php echo strip_tags(nl2br(($row['jobqualifications']))); ?></textarea>
    <input type="hidden" name="id2" value="<?php echo $_GET['id']; ?>" />
</fieldset>
<input name="Submit" type="submit" value="Update" />
</form>
<?php  } else {							
		$jobtitle = $_POST['jobtitle'];
		$jobdescription = $_POST['jobdescription'];
		$jobqualifications = $_POST['jobqualifications'];
					
	 $query = "UPDATE jobpost SET jobtitle= '$jobtitle', jobdescription= '$jobdescription', jobqualifications= '$jobqualifications'  WHERE id=$_GET['id']";
 $result = mysql_query($query) or die (mysql_error());

running this code give the following error:
Notice: Undefined index: id in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\pmd\edit_vacancies.php on line 17
select * from jobpost where id=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
Can someone please help!!!!!

[colweb]

<?php
// test if the variable id has been passed
// if id is there, $id will be the id value otherwise it will be null.
$id = isset($_GET['id']) ? $id = $_GET['id'] : null
if ($id == "") {
	// no id - through in an error and exit.
	echo "<p>Didn't recieve an id from you.</p>";
	exit();
}

// So we have an id (in $id)

$connection = mysql_connect($dbhost, $dbusername, $dbpassword) or die (mysql_error());
mysql_select_db($dbname, $connection);

// Don't use $_GET['id'] but use $id from this point on.
// -- rest of your code --

You should always use isset to see it a variable is passed. $_SERVER == 'GET' may not be populated on certain web-servers / configurations, whereas the $_GET array will always exist in PHP4 / 5.
I assume you now that using $_GET means your url should look like "http://localhost/edit_vacancies.php?id=123". If you forget to send the id this way, it will never be available in your php code (and isset will be false).