Supermarket Management System ERD models a complete point-of-sale and inventory database with seven core entities: Users, Categories, Suppliers, Products, Customers, Sales, and SaleDetails. Data flows from Categories and Suppliers into Products, while Users and Customers connect to Sales transactions, which then reference Products through SaleDetails line items. This normalized schema enforces referential integrity, supports multi-user operations, tracks inventory by category and supplier, and maintains a complete audit trail of customer purchases. Fork this diagram on Diagrams.so to customize entity attributes, add indexes, or extend with additional tables like Returns or Promotions. The design demonstrates OLTP best practices suitable for small-to-medium retail operations or as a foundation for larger enterprise POS systems.