Low-Level Design (LLD) is a crucial phase in the software development lifecycle where the system’s components and interactions are designed in detail. LLD focuses on the implementation of the design from a developer’s perspective, detailing class structures, databases, APIs, and algorithms. It is more granular than High-Level Design (HLD) and is critical for developers to understand the code implementation.
Types of Low-Level Design:
1. Class Design: Specifies the attributes, methods, and relationships between classes within an application.
Example:
public class User {
private String username;
private String password;
public void setUsername(String username) { this.username = username; }
public void setPassword(String password) { this.password = password; }
public String getUsername() { return username; }
public String getPassword() { return password; }
}
2. Sequence Design: Describes the flow of messages between objects to fulfill a particular task.
Example: A sequence diagram for a login process may show interactions between the User interface, the Authentication system, and the Database.
3. Database Design: Detailed table structures, relationships, indexes, and stored procedures are laid out for persistent storage.
Example:
CREATE TABLE Users (
user_id INT PRIMARY KEY,
username VARCHAR(50),
password_hash VARCHAR(255)
);
4. Interface Design: Defines the APIs or services to be exposed to other systems or components.
Example:
public interface AuthService {
boolean authenticate(String username, String password);
}
5. Component Design: This focuses on defining smaller units of the system, like modules or services, and their responsibilities.
Example: A Payment module might consist of classes and services that handle transaction processing and validation.
Importance of LLD:
LLD ensures that the design is not only functional but also efficient, maintainable, and scalable. It is key for developers as it provides the precise blueprint for implementation, ensuring that the system adheres to performance and security requirements.
In conclusion, LLD transforms abstract system architecture into a concrete framework, enabling developers to implement the system efficiently. Properly executed LLD helps in minimizing bugs, improving maintainability, and simplifying future enhancements. It aligns the technical implementation with the strategic objectives of the system design.
The article above is rendered by integrating outputs of 1 HUMAN AGENT & 3 AI AGENTS, an amalgamation of HGI and AI to serve technology education globally.