What are the reordering columns on laravel-backpack? - laravel-backpack

Question

In the official documentation, the following columns are mentioned :
parent_id
lft
rgt
depth
I haven't found any explanation of their types in the documentation. Could someone help me and tell me what they are ?
I also want to know if they are all mandatory if I only want to reorder a list of items (I don't need any nesting).
Edit: As this question is quite popular, I've updated the documentation with the correct info.

Answer 1

The reordering id columns should be integer or INT(10) if you're not using a migration.
Unfortunately they're all mandatory, yes. But if you're on a very strict DB schema, you could eliminate all of them except the "lft" column by adding this method to your EntityCrudController (basically overwriting the one in Backpack\CRUD\app\Http\Controllers\CrudFeatures\Reorder):
public function saveReorder()
{
$this->crud->hasAccessOrFail('reorder');
$all_entries = \Request::input('tree');
if (count($all_entries)) {
$count = 0;
foreach ($all_entries as $key => $entry) {
if ($entry['item_id'] != '' && $entry['item_id'] != null) {
$item = $this->crud->model->find($entry['item_id']);
$item->lft = empty($entry['left']) ? null : $entry['left'];
$item->save();
$count++;
}
}
} else {
return false;
}
return 'success for '.$count.' items';
}