This sales and inventory system data flow diagram level 2 depicts one of the business processes that can simplify and accelerate understanding, analysis, and representation. Level 2 data flow diagrams for sales and inventory systems reveal relationships among and between the various components in a program or system. DFDs are a useful technique for high-level modeling detail by demonstrating how to input data is transformed to output results via a series of functional transformations. Inventory Control System A data flow diagram is frequently used as a primary step to create an overview of the Inventory without getting into great detail, which can then be elaborated upon. It typically consists of overall application dataflow and Inventory process processes.