There are at least five ways to store a tree in PostgreSQL, for example: adjacency list, nested sets like MPTT Modified Preorder Tree Traversal, nested interval

There are at least five ways to store a tree in PostgreSQL, for example: adjacency list, nested sets like MPTT Modified Preorder Tree Traversal, nested intervals, Materialized Paths, ltree, JSON E.g. django-mptt : https://github.com/django-mptt/django-mptt/blob/main/mptt/models.py https://github.com/django-mptt/django-mptt/blob/main/mptt/mo... : indexed_attrs = (mptt_meta.tree_id_attr,) field_names = ( mptt_meta.left_attr, mptt_meta.right_attr, mptt_meta.tree_id_attr, mptt_meta.level_attr, ) Nested set model: https://en.wikipedia.org/wiki/Nested_set_model https://en.wikipedia.org/wiki/Nested_set_model : > The nested interval model stores the position of the nodes as rational numbers expressed as quotients (n/d).