Definition - What does Hierarchical Database mean?
A hierarchical database is a design that uses a one-to-many relationship for data elements. Hierarchical database models use a tree structure that links a number of disparate elements to one "owner," or "parent," primary record.
Techopedia explains Hierarchical Database
The idea behind hierarchical database models is useful for a certain type of data storage, but it is not extremely versatile. Its limitations mean that it is confined to some very specific uses. For example, where each individual person in a company may report to a given department, the department can be used as a parent record and the individual employees will represent secondary records, each of which links back to that one parent record in a hierarchical structure.
Hierarchical databases were popular in early database design, in the era of mainframe computers. While some IBM and Microsoft models are still in use, many other types of business databases use more flexible models to accommodate more sophisticated types of data management. Hierarchical models make the most sense where the primary focus of information gathering is on a concrete hierarchy such as a list of business departments, assets or people that will all be associated with specific higher-level primary data elements.