多级菜单项删除递归功能

Question

I want to delete category from multilevel menu with recursion function. To understand situation more carefully , lets take a look first at mysql table structure

CREATE TABLE IF NOT EXISTS menu(
id INT(5) NOT NULL AUTO_INCREMENT PRIMARY KEY,
p_id INT(5),
sort_id INT(5) NOT NULL,
title VARCHAR(50) CHARSET utf8 COLLATE 'utf8_unicode_ci' NOT NULL,
);

it looks like this when it is retrieved

  id  |  p_id  |  sort_id  | title  |

   1  |    0   |     1     | root1  |
   2  |    1   |     1     |  sub of root1
   3  |    0   |     2     | root2  |
   4  |    2   |     1     |  sub of "sub of root1"
  ... |  ...   |    ...    |   ....
etc ...

I've written php script for delete category, here it is =>

function del_cat($connection,$id){
        if (!$connection->connect_errno){
        if ($connection->set_charset("utf8")){
            if ($r = $connection->query("SELECT id FROM menu WHERE p_id=" . $id . "")){
            if ($r->num_rows>0){
                while ($row = $r->fetch_assoc()){
                del_cat($connection,$row['id']);
                }
            } else {
                $connection->query("DELETE FROM menu WHERE id=" . $id . "");
            }
            $r->free();
            }
        }
        }
    }

$connection variable is a just mysql connection object, and $id is id in table.

It works just fine when I'm deleting one row ( I mean when category doesn't have a child , sub categories), for example 1 | 0 | 1 | root1 |, but when I want to delete for example 4 | 2 | 1 | sub of "sub of root1" it doesn't delete category with sub categories . Any idea how to solve this problem ? thanks

Answer 1

The delete is only in else so you never actually delete the parent category. I think you need something like:

   del_cat($connection, $row['id']);
   $connection->query("DELETE ...");
} else {
   $connection->query("DELETE ...");

By the way you should escape the ID input.