The root node of that tree is an empty node.
The tree structure used in hierarchical models is called as routed true.
It consists of a collection of records that are connected to each other by links. The features of hierarchical model are as follows − It is used to specify the overall logical structure of the database. Record based logical models − These models are used in describing the data at the logical and view level. This model is used to describe the data at the internal level. Physical Model − These models describe how the data is stored in the computer.
This model can be used to describe the data at the conceptual and external level. Object Model − It uses concepts like entities, attributes, and their relationship. Data Models in the Database Management System (DBMS)are divided into three categories.
