Level 1 Data Flow Diagram for a customer purchase process spanning product selection, inventory validation, cost calculation, payment processing, and sales record updates. The workflow begins when a customer selects products, triggering availability checks against the Inventory Records datastore, followed by total cost calculation and payment receipt. Upon successful payment, a receipt is generated for the customer while sales records are simultaneously updated in the Sales Records datastore. This DFD captures the complete order-to-fulfillment sequence, making it ideal for documenting business requirements and identifying system boundaries. Fork this diagram on Diagrams.so to customize process steps, add error handling flows, or integrate additional datastores for your specific e-commerce platform.