PHP + MySql: a particular DELETE function - php

Question

I have a table with all the product's info.
PRODUCT TABLE
produc_id
product_name
img1
img2
img3
I created a page to update the product's info. My problem is how to manage the images. In the variables img1, img2 and img3 I saved the path of the images. Now i would like to delete that record with a link in the update.php page.
I tried something like this:
<a href="delete_img.php?id=<?php echo $img1; ?>&product_id=<?php echo $product_id; ?>">
the delete_img.php page is:
<?php
include '../asset/inc/auth.inc.php';
include '../asset/inc/db.inc.php';
$db = mysql_connect(MYSQL_HOST, MYSQL_USER, MYSQL_PASSWORD) or
die ('Unable to connect. Check your connection parameters.');
mysql_select_db(MYSQL_DB, $db) or die(mysql_error($db));
$img1 = (isset($_GET['img1'])) ? $_GET['img1'] : 0;
$product_id = (isset($_GET['product_id'])) ? $_GET['product_id'] : 0;
$query = 'UPDATE product SET img1=NULL WHERE product_id = ' . $product_id;
// invio la query
$result = mysql_query($query);
if (!$result) {
die("Errore nella query $query: " . mysql_error());
}
// close
mysql_close();
header('Refresh: 0; URL=update_immobile.php?id=' . $immobile_id . '');
?>
It works fine, but just for the single variable img1. For the second image, if I want to delete it i need another delete_img.php script (delete_img2.php) and so on.
Question: how can I optimize this 'function'?

Answer 1

You can optimize this function in a lot of different ways. In the $imgid could be the ID of the image stored (1, 2 or 3), therefore the HTML code would look as followed:
<a href="delete_img.php?id=<?=$imgid?>&product_id=<?php echo $product_id; ?>">
With this information submitted you can easily alter your MySQL query in the PHP code.
switch($_GET["id"]) {
case 1:
case 2:
case 3:
$field = "img" . $_GET["id"] ;
break ;
default:
$field = "" ;
}
if($table!="") {
$query = "UPDATE product SET $field=NULL WHERE product_id = $product_id";
$result = mysql_query($query);
}
More suitable would be, if you would create two more tables:
a table which stores the image + path
an intermediary table which links the image to a product
This way a product can store more than only three images and multiple products can have the same image. Also every image gets a unique ID to delete it (which would make your problem easier to solve).

Answer 2

This should work with as many image columns you have (not tested, but you get the idea):
<?php
include '../asset/inc/auth.inc.php';
include '../asset/inc/db.inc.php';
$db = mysql_connect(MYSQL_HOST, MYSQL_USER, MYSQL_PASSWORD) or
die ('Unable to connect. Check your connection parameters.');
mysql_select_db(MYSQL_DB, $db) or die(mysql_error($db));
$img = (isset($_GET['img1']) && in_array(key($_GET['img1'], array('img1', 'img2', 'img3')))) ? key($_GET['img1']) : 0;
$product_id = (isset($_GET['product_id'])) ? (int)$_GET['product_id'] : 0;
if ($img !== 0) {
$query = 'UPDATE product SET ' . $img . '=NULL WHERE product_id = ' . $product_id;
// invio la query
$result = mysql_query($query);
}
if (!$result) {
die("Errore nella query $query: " . mysql_error());
}
// close
mysql_close();
header('Refresh: 0; URL=update_immobile.php?id=' . $immobile_id . '');
?>
Some notes:
* don't forget to validate user input (I made some small tweaks to the code)
* always use exit or die after sending a redirect header, otherwise anyone could access your admin area with no username/password required

Answer 3

$img1 = (isset($_GET['img1'])) ? $_GET['img1'] : 0;
$img2 = (isset($_GET['img2'])) ? $_GET['img2'] : 0;
$img3 = (isset($_GET['img3'])) ? $_GET['img3'] : 0;
$query = 'UPDATE product SET if($img1==0) img1=NULL' ;
$query .= 'if($img2==0) ,img2=NULL' ;
$query .= 'if($img3==0) ,img3=NULL' ;
$query .= 'WHERE product_id = ' . $product_id'
$result = mysql_query($query);
It is simply concatenation of query with if condition.