🗄️ Database Models

🗄️ Database Models

Interactive learning module — Definition • Working • Advantages • Disadvantages • Uses

What is a Database Model?

A database model is a logical structure that describes how data is stored, organized, connected, and accessed inside a database.

👉 Click any button below to explore the database model.

🌳 Hierarchical Database Model

Definition: The hierarchical model organizes data in a tree-like structure consisting of parent and child records.

University

→

Department

→

Student

⚙️ How It Works

Data starts from a root node.

The root can have multiple child nodes, but each child generally has one parent.

Example:
University → Computer Science → Student

✅ Advantages

• Simple tree structure.
• Fast navigation for hierarchical data.
• Easy to understand.
• Good performance for predefined relationships.

❌ Disadvantages

• Many-to-many relationships are difficult.
• Data duplication can occur.
• Structural changes can be difficult.
• Less flexible than relational databases.

🎯 Uses

• File systems
• Organization structures
• XML data
• Directory systems

🕸️ Network Database Model

Definition: The Network Model represents data as a collection of records connected through relationships. Unlike the hierarchical model, a record can have multiple parent records.

Student

↔

Course

↔

Teacher

⚙️ How It Works

Records are connected through links.

A student can take multiple courses and a course can contain multiple students.

This supports many-to-many relationships.

✅ Advantages

• Supports complex relationships.
• Efficient navigation.
• Supports many-to-many relationships.
• Less duplication in some structures.

❌ Disadvantages

• Complex database design.
• Difficult for beginners.
• Structural changes can be difficult.
• Less commonly used today.

🎯 Uses

• Telecommunication systems
• Manufacturing systems
• Complex legacy systems
• Systems with interconnected records

📊 Relational Database Model

Definition: The relational model stores data in tables consisting of rows and columns. It is one of the most widely used database models.

Student_ID	Name	Course
101	Rahul	BCA
102	Anita	BCA

⚙️ How It Works

Each table represents an entity.

Rows represent records.
Columns represent attributes.

Tables can be connected using Primary Keys and Foreign Keys.

✅ Advantages

• Easy to understand.
• Uses SQL.
• Strong data integrity.
• Supports relationships between tables.
• Excellent for structured data.

❌ Disadvantages

• Complex joins can become expensive.
• Schema changes may require planning.
• Horizontal scaling can be more difficult.
• Not ideal for every type of unstructured data.

🎯 Uses

• Banking systems
• College management systems
• Hospital databases
• Payroll systems
• Online shopping systems

🧩 Object-Oriented Database Model

Definition: The Object-Oriented model stores information as objects, similar to objects used in object-oriented programming.

Student Object

Name
Roll
Course

→

Methods

getName()
getCourse()

⚙️ How It Works

Data and operations can be grouped together inside objects.

Objects can support concepts such as:

• Encapsulation
• Inheritance
• Polymorphism

✅ Advantages

• Works naturally with OOP languages.
• Supports complex objects.
• Supports inheritance.
• Useful for multimedia and engineering applications.

❌ Disadvantages

• More complex than relational databases.
• Less widely adopted.
• May require specialized knowledge.

🎯 Uses

• CAD/CAM systems
• Multimedia applications
• Engineering systems
• Scientific applications

🔗 Object-Relational Database Model

Definition: The Object-Relational model combines the traditional relational model with selected object-oriented features.

Relational Tables

+

Objects

→

Object-Relational DB

⚙️ How It Works

The database continues to use tables and SQL but can also support more complex data types and object-like structures.

✅ Advantages

• Combines relational and object features.
• Supports complex data types.
• Can retain SQL capabilities.
• Useful for complex applications.

❌ Disadvantages

• More complex than a basic relational model.
• Requires understanding of additional concepts.
• Implementation can vary between systems.

🎯 Uses

• Geographical information systems
• Engineering databases
• Scientific applications
• Complex business applications

⚡ NoSQL Database Model

Definition: NoSQL databases provide flexible approaches for storing data that does not necessarily fit the traditional relational table model.

Application

→

NoSQL Database

→

Flexible Data

⚙️ Major Types

1. Document Database
Stores JSON-like documents.

2. Key-Value Database
Stores data as key-value pairs.

3. Column-Family Database
Stores data in column-oriented structures.

4. Graph Database
Stores entities and their relationships as nodes and edges.

✅ Advantages

• Flexible schema.
• Suitable for large-scale applications.
• Can support horizontal scaling.
• Useful for rapidly changing data.
• Good for many distributed applications.

❌ Disadvantages

• Different NoSQL systems have different data models.
• Some systems provide fewer traditional relational features.
• Data consistency approaches vary.
• Migration between different systems may be difficult.

🎯 Uses

• Big Data applications
• Real-time applications
• Social media platforms
• IoT applications
• Content management

📚 Quick Comparison

Model	Structure	Best For
Hierarchical	Tree	Parent-child data
Network	Graph-like records	Complex relationships
Relational	Tables	Structured data
Object-Oriented	Objects	Complex objects
Object-Relational	Tables + Objects	Complex structured data
NoSQL	Document/Key-Value/Graph/etc.	Flexible and distributed data

B.K. PAUL

Bhairab Ganguly College

Database Management System • Interactive Learning Module

© 2026 B.K. PAUL • Bhairab Ganguly College