index error in database reading PHP script [duplicate] - php

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Closed 10 years ago.
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PHP: “Notice: Undefined variable” and “Notice: Undefined index”
So Im back with another php error, that I cant solve. But Im getting better:)
I have created a simple script that stores images in a database, I have no problems to store the file, but when Im reading the file i get an index error. It says
Notice: Undefined index: id in C:\wamp\www\gallery2\show.php on line
13
I cant really get what the problem is since Im thinking that everything is correct !?
the code for showing the images are
<?php
$username = "root";
$password = "";
$host = "localhost";
$database = "guestbook";
#mysql_connect($host, $username, $password) or die("Can not connect to database: ".mysql_error());
#mysql_select_db($database) or die("Can not select the database: ".mysql_error());
$id = $_GET['id'];
if(!isset($id) || empty($id)){
die("Please select your image!");
}else{
$query = mysql_query("SELECT * FROM tbl_images WHERE id='".$id."'");
$row = mysql_fetch_array($query);
$content = $row['image'];
header('Content-type: image/jpg');
echo $content;
}
?>

Answer 1

You are trying to access $_GET['id']. However, if no argument id is present in the querystring of the request, the index id will not be available in the $_GET superglobal. That's why you receive the notice.
So you should be doing something like this:
$id = !empty( $_GET[ 'id' ] ) ? $_GET[ 'id' ] : null;

Answer 2

It is telling you the value id does not exist in the $_GET array. Does the URL you are accessing have a ?id=something on it?

Answer 3

The variable...
$_GET['id'];
...doesn't contain a value, therefore it is not defined.
Check if your form mechanism leading to this $_GET is working, maybe var_dump it.
If your script should cope with an empty variable there, maybe check this variable first, something like this:
$id = "";
if (isset($_GET['id']) { $id = $_GET['id']; }