Building a Spring Boot Application for Oracle Database Integration

Application Integration Phase Roadmap

1. Choose Your Technology Stack for Integration

• Primary Recommendation: Java (Spring Boot)
  • Why?
    • Your end goal involves Java (Spring Boot) along with Apache Spark and Delta Lake. Starting with Spring Boot now will help you become familiar with the ecosystem.
  • Alternatives:
    • While Node.js is an option for quick prototyping, using Java from the start will reduce migration overhead later when you integrate with Spark and Delta Lake.

2. Set Up Your Spring Boot Project

• Project Initialization:
  • Use Spring Initializr (https://start.spring.io) or your favorite IDE to create a new Spring Boot project.
  • Include dependencies such as:
    • Spring Web (for building REST APIs)
    • Spring Data JPA (for ORM and CRUD operations)
    • Oracle JDBC Driver (to connect to your Oracle database)
• Configuration:
  • Configure your application's properties (or YAML) file with your Oracle database connection details (URL, username, password, etc.).

3. Map Your Database Schema to Java Entities

• Entity Classes:
  • Create Java entity classes corresponding to your tables (e.g., Customer, Order, Product, OrderItem, Shipment).
  • Use JPA annotations (such as @Entity, @Table, @Id, and @ManyToOne/@OneToMany) to map these classes to your Oracle tables.
• Repository Interfaces:
  • Define Spring Data JPA repository interfaces for each entity to abstract your CRUD operations.

4. Build RESTful API Endpoints

• Controller Layer:
  • Develop REST controllers that expose endpoints to perform CRUD operations on your entities.
  • This might include endpoints like:
    • GET /customers – list all customers
    • POST /orders – create a new order
    • PUT /order-items/{id} – update an order item
    • DELETE /shipments/{id} – delete a shipment record
• Service Layer (Optional but Recommended):
  • Consider adding a service layer to encapsulate business logic. This is particularly useful as your application grows in complexity.

5. Test Your Application

• Local Testing:
  • Use Postman, cURL, or your browser to test the API endpoints.
  • Verify that your CRUD operations correctly interact with the Oracle database.
• Logging & Debugging:
  • Ensure that logging is configured to help you diagnose any issues as you integrate.

6. Align with Your End Goal

• Keep the Bigger Picture in Mind:
  • Your final target is a full e-commerce data lake pipeline that integrates:
    • Oracle Database – your current data store.
    • Apache Spark – for large-scale data processing.
    • Delta Lake – for efficient storage and transactional guarantees on data lakes.
    • Java (Spring Boot) – for the API layer and orchestration.
• Forward Planning:
  • As you build your Spring Boot application, think about how you might extend it to:
    • Trigger or schedule Spark jobs.
    • Interface with Delta Lake (which can be done using Spark connectors).
    • Monitor and report on data processing jobs.
  • Document your design decisions and ensure your codebase is modular enough to allow these extensions later.

Build and Run Commands

./gradlew clean build -x test
./gradlew bootRun
./gradlew bootRun --debug

Database Security Best Practices

Avoid Using SYS for Application Connections:

It's generally not recommended to use the SYS account for application-level access, as it's reserved for database administration.

Solution:

• Create a dedicated user for your application in the Oracle database with appropriate privileges:

CREATE USER ecommerce_user IDENTIFIED BY strong_password;
GRANT CONNECT, RESOURCE TO ecommerce_user;