Question

Problem:

I am trying to delete all sublevels of a category by using a class. Currently I can only make it delete two sublevels, not three.

The database table:

CREATE TABLE betyg_category (
  CID int(11) NOT NULL AUTO_INCREMENT,
  Item varchar(100) NOT NULL,
  Parent int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (CID)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;

The PHP class:

<?php
class ItemTree 
{ 
   var $itemlist = array();

   function ItemTree($query)
   {
      $result = mysql_query($query) or die ('Database Error (' . mysql_errno() . ') ' . mysql_error());

      while ($row = mysql_fetch_assoc($result)) 
      {
         $this->itemlist[$row['CID']] = array(
           'name'   => $row['Name'],
           'parent' => $row['Parent']
         );
      }
   }

   function get_tree($parent, $with_parent=0)
   {
      $item_tree = array();

      if ($with_parent == 1 && $parent != 0) 
      {
         $item_tree[$parent]['name'] = $this->itemlist[$parent]['name'];
         $item_tree[$parent]['parent'] = $this->itemlist[$parent]['parent'];
         $item_tree[$parent]['child'] = $this->get_tree($parent);

         return $item_tree;
      }

      foreach ($this->itemlist as $key => $val) 
      {
         if ($val['parent'] == $parent) 
         {
               $item_tree[$key]['name'] = $val['name'];
               $item_tree[$key]['parent'] = $val['parent'];
               $item_tree[$key]['child'] = $this->get_tree($key);
         }
      }

      return $item_tree;
   }

   function make_optionlist ($id, $class='', $delimiter='/')
   {
      $option_list = '';

      $item_tree = $this->get_tree(0);

      $options = $this->make_options($item_tree, '', $delimiter);

      if (!is_array($id)) 
      {
         $id = array($id);
      }

      foreach($options as $row) 
      {
         list($index, $text) = $row;
         $selected = in_array($index, $id) ? ' selected="selected"' : '';
         $option_list .= "<option value=\"$index\" class=\"$class\"$selected>$text</option>\n";
      }

      return $option_list;
   }

   function make_options ($item_tree, $before, $delimiter='/')
   {
      $before .= empty($before) ? '' : $delimiter;

      $options = array();

      foreach ($item_tree as $key => $val) 
      {
         $options[] = array($key, '-&nbsp;'.$before.$val['name']);
         if (!empty($val['child'])) {
            $options = array_merge($options, $this->make_options($val['child'], $before.$val['name'], $delimiter));
         }
      }

      return $options;
   }

   function get_navlinks ($navid, $tpl, $startlink='', $delimiter=' &raquo; ')
   {
      // $tpl typ: <a href="index.php?id={id}" class="navlink">{name}</a>

      $search = array('{id}', '{name}');

      $navlink = array();

      while (isset($this->itemlist[$navid])) 
      {
         $replace = array($navid, $this->itemlist[$navid]['name']);
         $navlink[] = str_replace($search, $replace, $tpl);
         $navid = $this->itemlist[$navid]['parent'];
      }

      if (!empty($startlink)) 
      {
         $navlink[] = str_replace($search, array(0, $startlink), $tpl);
      }

      $navlink = array_reverse($navlink);

      return implode($delimiter, $navlink);
   }

   function show_tree ($parent=0, $tpl='%s', $ul_class='', $li_class='')
   {
      $item_tree = $this->get_tree($parent);

      return $this->get_node($item_tree, $parent, $tpl, $ul_class, $li_class);
   }

   function get_node ($item_tree, $parent, $tpl, $ul_class, $li_class)
   {
      // $tpl typ: <a href="item.php?id={id}" class="treelink" style="color:blue">{name}</a>

      $search = array('{id}', '{name}'); 

      $output = "\n<ul class=\"$ul_class\">\n";

      foreach ($item_tree as $id => $item) 
      {
         $replace = array($id, $item['name']);
         $output .= "<li class=\"$li_class\">".str_replace($search, $replace, $tpl);
         $output .= !empty($item['child']) ? "<br />".$this->get_node ($item['child'], $id, $tpl, $ul_class, $li_class) : '';
         $output .= "</li>\n";
      }

      return $output . "</ul>\n"; 
   }

   function get_id_in_node ($id)
   {
      $id_list = array($id);

      if (isset($this->itemlist[$id])) 
      {
         foreach ($this->itemlist as $key => $row) 
         {
            if ($row['parent'] == $id) 
            {
               if (!empty($row['child'])) 
               {
                 $id_list = array_merge($id_list, get_id_in_node($key));
               } else 
               {
                 $id_list[] = $key;
               }
            }
         }

      }
      return $id_list;
   }

   function get_parent ($id)
   {
      return isset($this->itemlist[$id]) ? $this->itemlist[$id]['parent'] : false;
   }

   function get_item_name ($id)
   {
      return isset($this->itemlist[$id]) ? $this->itemlist[$id]['name'] : false;
   }
}
?>

Scenario:

Say you have the following structure in a :

• Literature
• — Integration of sources
• —- Test 1

It will result in the following in the database table:

When I try to delete this sublevel, it will leave the last sublevel in the database while it should delete it. The result will be:

The PHP code:

//Check if delete button is set
if (isset($_POST['submit-deletecategory'])) 
{
    //Get $_POST variables for category id
    $CategoryParent = intval($_POST['CategoryList']);

    //Check if category is selected
    if ($CategoryParent != "#") 
    {
        //Get parent category and subsequent child categories
        $query = "SELECT CID, Item AS Name, Parent FROM " . TB_CATEGORY . " ORDER BY Name";
        $items = new ItemTree($query);

        if ($items->get_item_name($_POST['CategoryList']) !== false) 
        {
            //Build up erase list
            $CategoryErase = $items->get_id_in_node($CategoryParent);
            $CategoryEraseList = implode(", ", $CategoryErase);
        } 
        else 
        {
            $CategoryEraseList = 0;
        }

        //Remove categories from database
        $query = "DELETE FROM " . TB_CATEGORY . " WHERE CID IN ($CategoryEraseList)";
        $result = mysql_query($query) or die ('Database Error (' . mysql_errno() . ') ' . mysql_error());

       //Return a confirmation notice
       header("Location: settings.php");
       exit;
    }
}

Thank you in advance for any guidance I can get to solve the issue.

Answer 1

Here is a way to do it : use a recursive function, which will first look for the leaf item (the deepest in your tree). You remove children first, then the parent. And for each child, you remove child’s children first, etc…

deleteSub(1);

function deleteSub($cat_id) {
    $request = "SELECT * FROM ". TB_CATEGORY ." WHERE Parent = ".$cat_id;
    $results = mysql_query($request);
    while($child = mysql_fetch_array($results)) 
    {
        deleteSub($child["CID"]);
    }
    $request = "DELETE FROM ". TB_CATEGORY ." WHERE CID = ".$cat_id;
    return mysql_query($request);
}

A better way could be use this kind of recursive function to store CIDs in an array, then make a single DELETE request, but I think you’ll be able to adapt this code.