A hierarchical database design uses a parent-child structure where one parent has multiple child records while one child links to only one parent. In this tree-like data model, data is stored in records as fields with no more than one value. The parent, or root, data directory branches into child records that can further link to other subdirectory branches.
To retrieve data from a hierarchical database, you must start from the parent and go through all branches. This database model is not flexible enough to suit modern business database requirements.