As a CUSTOMER, I want to:
  - Browse and search products
  - Add products to cart (future)
  - Place an order with multiple items
  - View my order history
  - Cancel an unpaid order within 30 minutes
  - Pay for an order
  - View payment status

As an ADMIN, I want to:
  - Manage products (CRUD)
  - View all orders
  - Cancel any order
  - Process refunds
  - View business statistics

Execution Successful

CREATE TABLE users (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL UNIQUE,
    email VARCHAR(100) NOT NULL UNIQUE,
    password_hash VARCHAR(255) NOT NULL,
    role VARCHAR(20) NOT NULL DEFAULT 'CUSTOMER',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

CREATE TABLE products (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(200) NOT NULL,
    sku VARCHAR(20) NOT NULL UNIQUE,
    price DECIMAL(10,2) NOT NULL,
    stock INT NOT NULL DEFAULT 0,
    category VARCHAR(50),
    status TINYINT NOT NULL DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    INDEX idx_product_name (name),
    INDEX idx_product_category (category)
);

CREATE TABLE orders (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    user_id BIGINT NOT NULL,
    order_number VARCHAR(20) NOT NULL UNIQUE,
    status VARCHAR(20) NOT NULL DEFAULT 'PENDING',
    total_amount DECIMAL(10,2) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    INDEX idx_order_user (user_id),
    INDEX idx_order_status_created (status, created_at DESC),
    FOREIGN KEY (user_id) REFERENCES users(id)
);

CREATE TABLE order_items (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    order_id BIGINT NOT NULL,
    product_id BIGINT NOT NULL,
    quantity INT NOT NULL,
    unit_price DECIMAL(10,2) NOT NULL,
    subtotal DECIMAL(10,2) NOT NULL,
    FOREIGN KEY (order_id) REFERENCES orders(id),
    FOREIGN KEY (product_id) REFERENCES products(id)
);

CREATE TABLE payments (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    order_id BIGINT NOT NULL UNIQUE,
    transaction_id VARCHAR(50) UNIQUE,
    method VARCHAR(20) NOT NULL,
    status VARCHAR(20) NOT NULL DEFAULT 'PENDING',
    amount DECIMAL(10,2) NOT NULL,
    paid_at TIMESTAMP NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (order_id) REFERENCES orders(id)
);

CREATE TABLE

// Success response
public record ApiResponse<T>(
    int code,
    String message,
    T data,
    Instant timestamp
) {
    public static <T> ApiResponse<T> success(T data) {
        return new ApiResponse<>(200, "OK", data, Instant.now());
    }
    public static <T> ApiResponse<T> created(T data) {
        return new ApiResponse<>(201, "Created", data, Instant.now());
    }
}

// Paged response
public record PagedResponse<T>(
    List<T> content,
    int page,
    int size,
    long totalElements,
    int totalPages
) {}

// Execution Successful

# List products with pagination, sorting, and filtering
GET /api/v1/products?page=0&size=20&sort=price,desc&category=electronics&minPrice=100&maxPrice=999

# Command executed successfully

# OrderFlow System Design Document

## 1. Business Requirements
- E-commerce order management system
- 4 modules: User, Product, Order, Payment
- 2 roles: CUSTOMER, ADMIN
- Expected: 10,000 DAU, 1,000 orders/day

## 2. Tech Stack
- Java 17 + Spring Boot 3.2.x
- MySQL 8.0 + Spring Data JPA
- Redis 7 + Caffeine (two-level cache)
- Spring Security + JWT (OAuth2 Resource Server)
- Docker + Kubernetes deployment

## 3. Database Design
- 5 tables: users, products, orders, order_items, payments
- Indexes on high-frequency query columns

## 4. API Specification
- RESTful API with versioning (/api/v1/)
- JWT Bearer authentication
- Unified response format: ApiResponse<T>
- Pagination: page, size, sort parameters

## 5. Non-functional Requirements
- P99 latency < 100ms
- Error rate < 0.1%
- Availability > 99.9%
- Automated test coverage > 80%