• Firstly we onboard the course (cohort, instructor, learners becomes null) course has Many Cohorts, Instructors, Learners

• Then we Onboard the Cohort for under any onboarded Course. Now if we fetch the perticular course, we can see the Cohort available under that course. Also if we fetch any cohort, we can see the under which course that cohort it is.

• Now we onboard the instrucor under the onboarded cource and cohort. If we fetch instructor, we see under which cohort and course it is. One instrucor has Many cohorts

Learner Management System

This project is a Spring Boot Learner Management System built for learning purposes. It uses H2 in-memory database and Spring Data JPA.

The primary focus of this project is modeling and designing REST APIs, including entity relationships, API endpoints, and basic CRUD operations.

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Tech Stack

• Java 21
• Spring Boot
• Spring Web
• Spring Data JPA
• H2 Database
• Gradle

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How to Run the Application

Run using Maven Wrapper

./mvnw spring-boot:run

OR run directly from your IDE by executing:

LearnerManagementSystemApplication.java

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Application URL

Once the application starts successfully, it will run on:

http://localhost:8080

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H2 Database Console

H2 is an in-memory database, mainly used for development and learning.

H2 Console URL

Open your browser and go to:

http://localhost:8080/h2-console

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H2 Console Login Details

Use the following details on the H2 login page:

Field	Value
JDBC URL	jdbc:h2:mem:lmsdb
Username	sa
Password	(leave empty)

Make sure the JDBC URL matches the one defined in application.properties.

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H2 Configuration (application.properties)

spring.h2.console.enabled=true
spring.h2.console.path=/h2-console

spring.datasource.url=jdbc:h2:mem:lmsdb
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

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Important Notes

• H2 in-memory database resets when the application restarts
• Tables are created automatically by Hibernate using JPA entities
• SQL queries will be printed in the console (for learning purposes)

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How to Verify Tables

1. Start the application
2. Open H2 console
3. Login using the details above
4. Click Connect
5. Run SQL query:

SELECT * FROM LEARNER;

(Replace LEARNER with your actual table name)

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Recommended Package Structure

com.airtribe.learnermanagementsystem
│
├── controller
├── service
├── repository
├── entity
├── dto
└── exception

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Learning Purpose

This project is created to understand:

• Spring Boot fundamentals
• REST APIs
• JPA & Hibernate
• Database integration using H2
• Layered architecture

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You are now ready to use the H2 Console and explore your database.

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Note:

• In a Many-to-Many relationship, normalization is achieved by creating a join table that stores the primary keys of both tables.

• In a One-to-Many / Many-to-One relationship, the primary key of the One side is used as a foreign key in the Many side table.

• In such relationships, the Many side is always the owner of the relationship, while the One side represents the back reference.

• Therefore, the Many-to-One entity is always the owner of the relationship, and the One-to-Many side acts as the back reference.