Nested sets have very efficient reads at the cost of high maintenance on write/delete operations.
Abstract model to create your own Nested Sets Trees.
Attribute: a list of model fields that will be used for node ordering. When enabled, all tree operations will assume this ordering.
node_order_by = ['field1', 'field2', 'field3']
|Returns:||A queryset of nodes ordered as DFS, including the parent. If no parent is given, all trees are returned.|
This metod returns a queryset.