The primary goal of this project is to practice working with relational databases. You will design a well-structured database schema, manage relationships between tables (Primary and Foreign Keys), and connect a Java application to a PostgreSQL database to perform CRUD operations.

You will implement a backend system where users can create accounts, view the restaurant's menu, place orders, and store all transaction data permanently in a database.

Tech Stack:

Language: Java 23
Build Tool: Maven
Database: PostgreSQL
API: JDBC

✅ Prerequisites

Before starting, ensure you have the following installed on your machine:

Git
Java 23 (JDK)
Maven
PostgreSQL
A PostgreSQL Database GUI (e.g., pgAdmin, DBeaver, or DataGrip)

⚙️ Maven Configuration

This project relies on Maven to manage dependencies. Your project must contain a pom.xml file configured for Java 23 and the PostgreSQL JDBC driver.

Example pom.xml snippet:

<properties>
    <maven.compiler.source>23</maven.compiler.source>
    <maven.compiler.target>23</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <postgresql.version>42.7.8</postgresql.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>${postgresql.version}</version>
    </dependency>
</dependencies>

🎯 Objectives

By completing this assignment, you will be able to:

Design a structured relational database schema.
Understand and implement database relationships (One-to-Many).
Work effectively with Primary Keys (PK) and Foreign Keys (FK).
Write SQL scripts to create tables and insert initial data.
Connect a Java application to PostgreSQL using JDBC.
Implement CRUD (Create, Read, Update, Delete) operations via Java.
Build a modular and object-oriented backend application.

🏗️ Database Entities & Schema

Your database must be created using a database.sql script.

The script must include:

Table creation statements
Keys and relationships
Appropriate constraints
Initial mock data

You are responsible for selecting appropriate:

Data types
Primary Keys
Foreign Keys
Constraints (e.g., NOT NULL, UNIQUE, CHECK, DEFAULT)

Your design decisions will be evaluated as part of the assignment.

1. User (Customer)

Represents a customer using the system.

Required Information:

Unique identifier
Username
Password
Email (optional)

Requirements:

Usernames must be unique.
Passwords must not be stored in plain text.
A user can place multiple orders.

2. MenuItem

Represents a food or drink available in the restaurant.

Required Information:

Unique identifier
Name
Description (optional)
Price
Category (optional)

Requirements:

Every item must have a positive price.
The database must contain at least 3 menu items inserted through the SQL script.

3. Order

Represents a specific order placed by a customer.

Required Information:

Unique identifier
Reference to the customer who placed the order
Creation date and time
Total price

Requirements:

An order belongs to exactly one user.
A user can have multiple orders.
An order can contain multiple items.

4. OrderDetail

Represents an item inside an order.

Required Information:

Unique identifier
Reference to an order
Reference to a menu item
Quantity
Item price at the time of purchase

Requirements:

Quantity must always be greater than zero.
The stored price should represent the item's price when the order was placed.
An order can contain multiple order details.

Design Notes

Before implementing the schema, identify:

The primary key of each entity.
The foreign key relationships.
Any uniqueness constraints.
Any required fields.
Any validation rules that should be enforced by the database.

Your schema should be normalized and designed to avoid unnecessary data duplication.

💻 Required Features & App Flow

You must create a Java application that communicates solely with PostgreSQL using JDBC. Do not store any application data in local text files.

Feature 1: User Management (Auth)

Register: Insert a new user. Verify the username is unique and hash the password before saving.
Login: Validate credentials against the database. Handle incorrect username or password scenarios gracefully.

Fetch and display all available MenuItem records from the database.

Feature 3: Order Creation

Allow the logged-in user to select items from the menu and specify a quantity.
Calculate the total price.
Save the Order record, and subsequently save the corresponding OrderDetail records.

Feature 4: Receipt Generation

After an order is placed, query the database to print a detailed receipt.
Must include: Item names, quantities, unit prices, subtotal per item, and the final grand total.

Feature 5: Order History (Bonus ⭐)

Allow a user to view all their past orders and the total amount spent on each.

To give you an idea of how your application should flow, here is a recommended structure for your Command Line Interface :

Plaintext

=======================================
      🍕 WELCOME TO JAVA PIZZERIA 🍕
=======================================
1. Login
2. Register New Account
3. Exit
=======================================
Choose an option: 1

[Login]
Enter username: ***
Enter password: ***

=======================================
          🍽️ MAIN MENU 🍽️
=======================================
1. View Menu
2. Place a New Order
3. View Order History (Bonus)
4. Logout
=======================================
Choose an option: 2

[Placing Order]
Available Items:
1. Pizza - $10.00
2. Burger - $8.00
3. Pasta - $12.00

Enter the ID of the item to add (or 0 to finish): 1
Enter quantity: 2
Added 2x Pizza to your cart.

Enter the ID of the item to add (or 0 to finish): 0

[Order Summary / Receipt]
---------------------------------------
Item         Qty     Unit      Total
---------------------------------------
Pizza        2       $10.00    $20.00
---------------------------------------
Final Total: $20.00
Order saved successfully!

📃 Evaluation Criteria

Your project will be graded based on the following:

1. Database Design:

Correct schema design with appropriately chosen data types.
Proper use of Primary Keys, Foreign Keys, and Constraints (e.g., NOT NULL, UNIQUE).
A working database.sql initialization script.

2. JDBC Integration:

Successful connection to PostgreSQL.
Use of PreparedStatement to prevent SQL injection.
Proper exception handling (SQLException).

3. Code Quality & OOP:

Clean structure (e.g., separating database logic into DAO classes).
Avoidance of code duplication.
Application successfully covers all required functionalities (Auth, Menu, Ordering, Receipts).

README.md

WS 10 - Restaurant Database Management System

📖 Overview

✅ Prerequisites

⚙️ Maven Configuration

🎯 Objectives

🏗️ Database Entities & Schema

1. User (Customer)

2. MenuItem

3. Order

4. OrderDetail

Design Notes

💻 Required Features & App Flow

Feature 1: User Management (Auth)

Feature 2: Menu Browsing

Feature 3: Order Creation

Feature 4: Receipt Generation

Feature 5: Order History (Bonus ⭐)

📱 Sample Console Menu Template

📃 Evaluation Criteria