🛒 Online Sales Platform – Databases Project

📌 Overview

The system was built with a strong focus on transactional integrity, concurrency control, and security, using PostgreSQL and Python (Flask). It includes mechanisms such as:

• ACID-compliant transactions
• Row-level locking (SELECT FOR UPDATE)
• Isolation levels (REPEATABLE READ)
• Trigger-based notifications
• Versioning of product data

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⚙️ Technologies Used

• Python (Flask, psycopg2, JWT)
• PostgreSQL
• Docker & Docker Compose
• pgAdmin (for DB management)
• Postman (for API testing)

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📚 Project Structure

├── python/               # Python API source code
├── db/                   # PostgreSQL script
├── er/                   # Conceptual and physical database models (ER diagrams)
├── postman/              # Postman collection for API testing
├── report_PT/            # Report delivered

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🚀 How to Run the Project

1. Prerequisites

Make sure you have the following installed:

• Docker Desktop
• Postman
• pgAdmin

2. Setup Instructions

1. Configure the database:

   • Create a PostgreSQL database.
   • Update the Python source files with your DB credentials.

2. Edit Docker Compose:

   • Modify docker-compose-python-psql.yml with your DB settings.

3. Start the architecture:

   sh docker-compose-python-psql.sh

4. Import Postman collection:

   • Open Postman and import the collection from the postman/ folder.

5. Monitor operations:

   • Use pgAdmin to inspect database activity and validate transactions.

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🧠 Development Highlights

• Product versioning
• Unified Q&A table with boolean flag
• Concurrency control with locks and isolation levels
• JWT-based authentication
• Trigger-based notifications