Mergetable

Project Overview

Mergetable is a Spring Boot project that demonstrates entity merging using JPA event listeners. Instead of using database triggers, it listens for Hibernate insert events on the User and Address tables and updates a third table, OneForAll, which contains combined fields from both entities.

Features

• JPA Event Listeners: Automatically updates OneForAll when User or Address is created.
• No Database Triggers: Ensures data consistency at the application level.
• Simple API: Supports only create operations for testing merging.

Tech Stack

• Backend: Java (Spring Boot)
• Database: MySQL (or any relational database)
• ORM: Hibernate with JPA event listeners

How It Works

1. User Table → Stores user-related data.
2. Address Table → Stores address-related data.
3. OneForAll Table → Stores combined fields from User and Address.
4. JPA Event Listeners detect insert operations in User and Address and automatically populate OneForAll.

Installation & Setup

Prerequisites

• Java 17+
• MySQL database
• Maven

Steps

1. Clone the repository:

   git clone https://github.com/aditya9389/mergetable.git
   cd mergetable

2. Configure the database in application.properties:

   spring.datasource.url=jdbc:mysql://localhost:3306/mergetable
   spring.datasource.username=root
   spring.datasource.password=root
   spring.jpa.hibernate.ddl-auto=update

3. Run the application:

   mvn spring-boot:run

API Endpoint

Create User & Address (Triggers OneForAll Update)

• Endpoint: POST /create
• Description: Inserts a new user and address, triggering the OneForAll table update.
• Request Body Example:

  {
    "user": {
      "name": "John Doe",
      "email": "[email protected]"
    },
    "address": {
      "street": "123 Main St",
      "city": "New York"
    }
  }

Future Improvements

• Add update and delete event handling.
• Implement API for fetching merged data.
• Expand to support more entity relationships.

Contact

For any questions, feel free to reach out via email or GitHub issues.