What are the components of logical database model?

The components of a logical database model are the fundamental building blocks used to represent the structure and relationships of data within a database system. These components provide a blueprint for how data is organized and accessed.

Core Components

The three main components are:

• Entities: Represent real-world objects, concepts, or things about which the business needs to store information. Each entity represents a set of similar items. For example, Customer, Product, or Order.
• Attributes: Describe the characteristics or properties of an entity. Each attribute holds a single piece of information about the entity. For example, a Customer entity might have attributes like CustomerID, Name, Address, and Phone Number.
• Relationships: Define the associations or interactions between entities. They specify how entities are related to each other. For example, a Customer can place one or more Orders.

Explanation with example

To illustrate, consider a simplified e-commerce database:

Component	Description	Example
Entity	A person, place, thing, event, or concept about which data is collected. Represents a table in a relational database.	Customer, Product, Order
Attribute	A characteristic or property of an entity. Represents a column in a relational database table.	CustomerID, ProductName, OrderDate
Relationship	Defines how entities are related to each other. Represented by foreign keys in relational database tables.	Customer places Order. Order contains Product.

In this model:

• Customer, Product, and Order are entities. Each represents a table in a relational database.
• CustomerID, Name, Address are attributes describing the Customer entity.
• The relationship "Customer places Order" connects the Customer and Order entities.

Significance

These components are essential for:

• Data Organization: Structuring data in a logical and meaningful way.
• Data Integrity: Enforcing rules and constraints to maintain data accuracy.
• Database Design: Providing a blueprint for creating and implementing a database.
• Communication: Enabling stakeholders to understand the database structure.

Without these core components, a database would lack structure, consistency, and the ability to effectively manage and retrieve information.