Which database organization uses parent-child relationships to organize data in a tree-like structure?

The type of database organization that uses parent-child relationships to organize data in a tree-like structure is the Hierarchical Database Model.

In a Hierarchical Database Model, data is structured in a way that resembles a tree. Each node in this "tree" represents a record, and these nodes have a parent-child relationship. The root node is the top-most part of this structure, and each node can have zero or more child nodes. It functions similarly to a family tree where a parent can have multiple children, but each child has only one parent.

This approach makes retrieval of data in a structured and predictable manner very efficient, as navigating through the tree is straightforward. However, it also means there can be limitations, such as issues with representing complex many-to-many relationships, which can be more easily accommodated in other database models like relational databases.