Parent-child tree relationships are represented using a many-to-one relationship with the same model, where each record holds a reference to its parent. The inverse one-to-many relationship represents the record's direct children.

product.category model uses hierarchical data structures (parent-child relationships), Optimize hierarchy tree searching can be enabled by setting the _parent_store=True model attribute and adding the parent_path helper field. This helper field stores additional information about the hierarchy tree structure, which is used to run faster queries

Note: the parent_path field must also be added, and it must be indexed.