Data Flow Diagram

Inventory Control System An Inventory Control System (ICS) at its most basic tracks items available for sale and notifies you when your stock is running low. Assume this is a retailer and not a manufacturing firm so inventory increases when items are received from a supplier and decreases when items are sold to a customer. Inventory quantities are decreased based on data exchanged with the Sales Control System (SCS) and increased based on data exchanged with the Purchasing Control System (PCS). The SCS processes sales orders re- ceived from customers while the PCS processes purchase orders sent to suppliers. Assume that paying suppliers and invoicing customers are outside the scope of the ICS. The ICS uses a single data store named INVENTORY. If inventory-on-hand falls below a minimum order quantity, the ICS generates a pur- chase order request which is sent to the PCS. The PCS then creates and transmits a purchase order to the supplier. When the items are physically received, the PCS transmits the list of received items to the ICS. The SCS receives a sales order from the customer and transmits the inventory quantity to be de- creased to the ICS when an order has been approved for fulfillment. A complete data flow diagram (DFD) would likely include processes from the PCS and SCS subsystems but we will keep it simple for this assignment—stuff goes out and stuff comes in. In this assignment you will create two data flow diagrams representing the same system at different levels of detail. Remember the location of your system boundary—your area of study is the Inventory Control System! Assignment Draw two data flow diagrams of the Inventory Control System using Gane-Sarson symbols: 1) The con- text level (Level-0) DFD illustrating the system and its external entities and 2) the Level-1 (or Diagram-0) DFD illustrating the major processes and data stores. Make sure the two DFDs are balanced, that is in- puts and outputs match when comparing the two levels. Data flow lines do not indicate task sequence but rather streams of data moving to or from entities, processes, and data stores. Remember the nam- ing conventions, do not violate diagramming rules, and only use data flow lines with single arrow heads. Refer to the Data Flow Diagrams Study Guide for examples.