Amazon-style e-commerce ER diagram modeling a complete order-to-product data schema with USERS, ORDERS, PRODUCTS, and ORDER_ITEMS entities. The design captures one-to-many relationships between users and orders, and many-to-many relationships between orders and products through a junction table. Primary and foreign keys enforce referential integrity across customer accounts, order history, inventory tracking, and line-item details including quantity, pricing, and discounts. Fork this diagram to customize schemas for your own marketplace, add payment or review entities, or export as SQL DDL for immediate database implementation. The ORDER_ITEMS bridge table elegantly resolves the many-to-many relationship while preserving historical unit prices and discounts per transaction.