Using nested collection model to store Hierarchical data in sqlite, how can I move a category to another category

I am trying to store hierarchical data using SQLite. After a lot of searching, I decided to use a nested set model instead of an adjacency list since almost 90% of the operations will be counted and only 10% will be updated / deleted / created.

I followed this example: http://www.phpro.org/tutorials/Managing-Hierarchical-Data-with-PHP-and-MySQL.html

And it works great to add, remove and read new nodes.

But I didn't find an article explaining how to update the tree, for example. moving a category to another category.

Below is my database structure:

id   name   left_node   right_node
1    name1     1          2

      

        
        
        
      

    

** I didn't find a place explaining how to update the hierarchy that I really need. **

Another problem is

public function delete_node($pleft, $pright){

$width = $pright-$pleft+1;

$delete_sql = "delete from categories where left_node between $pleft and $pright";
$update_sql1 = "update categories set right_node = right_node-$width where right_node > $pright";
$update_sql2 = "update categories set left_node = left_node-$width where left_node> $pright";
//
$this->db->trans_start();
//
$this->db->query($delete_sql);

//
$this->db->query($update_sql1);
$this->db->query($update_sql2);
$this->db->trans_complete();
//
return $this->db->trans_status();
}

      

        
        
        
      

    

This is my removal method and it ends up. This is normal?

I solved the problem, thanks for the help http://www.ninthavenue.com.au/how-to-move-a-node-in-nested-sets-with-sql

I am using codeigniter with sqlite database. below is my function,

public function move_node($pleft, $pright, $origin_left_pos, $origin_right_pos){

//
//the new_left_position is different according to which way you want to move the node 
$new_left_position = $pleft + 1;
//
$width = $origin_right_pos - $origin_left_pos + 1;
$temp_left_position = $origin_left_pos;

$distance = $new_left_position - $origin_left_pos;
//backwards movement must account for new space
if($distance < 0){

  $distance -= $width;
  $temp_left_position += $width;

}
//
$update_sql1 = "update categories set left_node = left_node+$width where left_node >=  $new_left_position";

$update_sql2 = "update categories set right_node = right_node+$width where right_node >= $new_left_position";

//
$update_sql3 = "update categories set left_node = left_node+$distance , right_node = right_node+$distance where left_node >= $temp_left_position AND right_node < $temp_left_position+$width";

//
$update_sql4 = "update categories set left_node = left_node-$width where left_node > $origin_right_pos";
$update_sql5 = "update categories set right_node = right_node-$width where right_node > $origin_right_pos";

//

$this->db->trans_start();

$this->db->query($update_sql1);

//
$this->db->query($update_sql2);
$this->db->query($update_sql3);
$this->db->query($update_sql4);
$this->db->query($update_sql5);
$this->db->trans_complete();

return $this->db->trans_status();
}