Hierarchical Model in DBMS

This concept uses a hierarchical tree structure to organise the data. The hierarchy begins at the root, which contains root data, and then grows into a tree as child nodes are added to the parent node.

In this article, we will dive deeper into the Hierarchical Model in DBMS according to the GATE Syllabus for (Computer Science Engineering) CSE. Keep reading ahead to learn more.

Table of Contents

What is the Hierarchical Model in DBMS?
Features of a Hierarchical Model
Pros of Hierarchical Model
Cons of Hierarchical Model

What is the Hierarchical Model in DBMS?

The Hierarchical Model was the first database management system model. This concept uses a hierarchical tree structure to organise the data. The hierarchy begins at the root, which contains root data, and then grows into a tree as child nodes are added to the parent node. This model accurately depicts several real-world relationships such as food recipes, website sitemaps, and so on.

Example

The following diagram depicts the relationship between the shoes available on a shopping website:

Features of a Hierarchical Model

1. Parent-Child Relationship

A parent node exists for each child node. However, a parent node might have several child nodes. It is not permitted to have more than one parent.

2. One-to-many Relationship

The data is organised in a tree-like form, with the datatypes having a one-to-many relationship. There can only be one path from any node to its parent. For example, in the preceding example, there is only one way to get to the node ‘sneakers’, which is through the ‘men’s shoes’ node.

3. Deletion Problem

When a parent node is removed, the child node is removed as well.

4. Pointers

Pointers are used to connect the parent and child nodes and to traverse and navigate between the stored data. The ‘shoes’ node in the above example points to the two additional nodes, ‘women’s shoes’ and ‘men’s shoes.’

Pros of Hierarchical Model

A tree-like structure is incredibly straightforward and quick to navigate.
Any modification to the parent node is reflected automatically in the child node, ensuring data integrity.

Cons of Hierarchical Model

Relationships that are complex are not supported.
Because it only supports one parent per child node, if we have a complex relationship in which a child node needs to have two parents, we won’t be able to describe it using this model.
When a parent node is removed, the child node is removed as well.

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