Undefined index for delete page

Question

I'm trying to create a delete option for a table which is directly getting data from the mysql database. I have a function to display the table and want to add 'delete' button with each category. Somehow I get Undefined index for 'cat_id' which is 'category id'according to my table.

this is the function that i am using function dispcategories() { include ('connection.php');

    $select = mysqli_query($con, "SELECT * FROM categories");
    echo '';

    while ($row = mysqli_fetch_assoc($select)) {
        echo "<table class='category-table'>";
        echo "<tr><td class='main-category' colspan='2'>".$row['category_title']."</td></tr>
              <tr><td><a href='deletecategory.php?id=".$row['cat_id'].";? >'>delete</a></td></tr>;"; 
          dispsubcategories($row['cat_id']);

        echo "</table>";
    }
}

and this is what i have on my delete page

$id = $_GET['cat_id'];
$del = mysqli_query($con, "DELETE FROM `categories` WHERE id='$id'");

could you show us the column fields of your table? it seems cat_id doesn't exists in their table or maybe it has a different name. — Daniel Luna, Jun 25 '19 at 19:01
thankyou for the reply, i have the field directly made in my database table with the name cat_id — shazmeen_shauq, Jun 25 '19 at 19:15
1) you're open to SQL injection and should address immediately. 2) what's the rendered URI of delete? does it look like `?id=XX`? — treyBake, Jun 25 '19 at 21:38
@treyBake yes that's what i get in my url but $_GET doesnot seem to be getting this id — shazmeen_shauq, Jun 26 '19 at 08:09

score 0 · Answer 1 · answered Jun 25 '19 at 18:57

0

Remove ;?> from href='deletecategory.php?id=".$row['cat_id'].";?>' and also you don't need semi-colon here </tr>;

Then your url is deletecategory.php?id=xx so you should have $_GET['id'] instead of $_GET['cat_id']

answered Jun 25 '19 at 18:57

Astrea

148
9

thanks a lot for your help but my query still fails after these changes – shazmeen_shauq Jun 25 '19 at 19:13
$id=$_GET['id']; $del=mysqli_query($con,"DELETE FROM `categories` WHERE id='$id'"); if(!$del){ echo 'failed'; } – shazmeen_shauq Jun 25 '19 at 19:13
So you use `categories.cat_id` to delete `categories.id`, is it expected? – Astrea Jun 25 '19 at 19:21
yes, i want to delete the specific id that is selected – shazmeen_shauq Jun 25 '19 at 19:25

score -1 · Answer 2 · edited Jun 25 '19 at 19:29

-1

Try to modify your code as follows

$select = mysqli_query($con, "SELECT category_title, cat_id FROM categories");

    echo "<table class='category-table'>";

while ($row = mysqli_fetch_assoc($select)) {
    if(!isset($row['cat_id'])
         continue;

    echo "<tr>
              <td class='main-category' colspan='2'>".$row['category_title']."</td>
              <td><a href='deletecategory.php?id=".$row['cat_id']."'>delete</a></td>
         </tr>;"; 
      // dispsubcategories($row['cat_id']); // I don't know the use of this but try to comment it

}
    echo "</table>";

Regards

edited Jun 25 '19 at 19:29

Astrea

148
9

answered Jun 25 '19 at 19:24

Daniel Luna

341
2
9

this code is working good thanks for that,because it takes the id correctly in the url, the problem seems to be with the query on the delete page which is failing $id=$_GET['id']; $del=mysqli_query($con,"DELETE FROM `categories` WHERE id='$id'"); – shazmeen_shauq Jun 25 '19 at 19:43
Assigne the query to a variable: $query = "DELETE FROM categories WHERE id=$id"; $select = mysqli_query($con, $query); – Daniel Luna Jun 25 '19 at 20:38
1

@DanielLuna that query is open to SQL injection ... – treyBake Jun 25 '19 at 21:39
@user1234 is that field nullable? – treyBake Jun 25 '19 at 21:39
@treyBake no the field is not nullable – shazmeen_shauq Jun 26 '19 at 08:33
@user1234 then cat_id should never be unset – treyBake Jun 26 '19 at 12:38
@user1234 do you still have problems with the query? – Daniel Luna Jun 26 '19 at 13:43
1

@DanielLuna no i solved it, I had foreign keys in my table which was causing the query to fail, I did the cascade on delete in the tables and it worked fine, thanks a lot for your help – shazmeen_shauq Jun 27 '19 at 08:26

Undefined index for delete page

2 Answers2