Question

Thorn Kites, Inc. sells a range of kitesurfing equipment via its website. The order fulfillment is to be handled by a new information system called the Ordering System (OS). Use a data flow diagram to model the requirements for the new system. Create a Context diagram and Diagram 0 (one level below the context diagram). Customer can place an online order through a customer-facing part of the Ordering System (OS) which checks the customer data in the Customer file datastore and then checks with the Warehouse system if products are available. Warehouse sends back the status of the requested product to the OS which communicates the status of the order back to the customer together with the data about the invoice. The customer sends payment information and the OS creates a pending order by saving the order in the Order file datastore. The Ordering system also sends a shipping information to the Warehouse system for the order to be shipped. Once the product ships, the Warehouse system sends shipping confirmation to the OS, which changes the pending order to a completed order in the Order File datastore. The Manager can access the Order file datastore and modify the data. Similarly, the manager an access the Customer file datastore and modify its data.

Context Diagram: Draw a context diagram showing what data external entities exchange with the Ordering system (OS). Draw the data flows and label them. There are 3 entities: Customer, Warehouse system, and Manager. Make sure that the data flows match those from diagram 0.

Diagram 0: Diagram 0 shows more details of the system. This is one possible interpretation of the description above. More or less details is possible, as well as different division of responsibilities among the sub-processes.

The sub-process that handles all communication with the customer is positioned between the customer entity and the rest of the system. It handles formatting of messages for the customer. This process accesses the Customer file datastore (bidirectional for read/write).

There is a process that initiates the creation of a new order by first checking with the warehouse about availability of the products. It then sends the response to the customer-facing process, along with invoice details (it also accesses the Customer file for invoicing details such as discounts). The process forwards the order details to another process that generates the shipping information and records the order as a pending order in the Order file.

Once the products are shipped, the warehouse system sends a confirmation to a process that is in charge of completing the order by updating the pending order to a completed order in the Order file.

Finally, there is the capability for the manager to read and modify the order file as well as the customer file.

Sample solution

You may make additional assumptions regarding this model. The information below is a guide and it is not the only appropriate way to model this situation.

"1.0 Communicate with customer" receives order information and payment from the customer and sends status information and invoice to the customer. It transforms the data into system-specific format and sends the order details, payment details to 2.0 Initiate order. It also reads and writes customer data from/to Customer file datastore.

"2.0 Initiate order" receives the order details and payment details from 1.0 and sends a product query message to the warehouse. The warehouse response called product availability is forwarded as availability details to 1.0. Also, invoice details are sent to 1.0 based on invoicing data read from the Customer file datastore. Finally, customer and order details are send to 3.0 Generate shipping order.

"3.0 Generate shipping order" sends shipping information to the warehouse system for actual shipping of the products. It makes a record in the Order file datastore by sending it pending order details. Order details are also sent to 4.0 Complete order process once requested by it upon shipping of products.

"4.0 Complete order" receives a shipping confirmation from the warehouse once products ship. It receives the order details from 3.0 and reads the pending order details from the Order file datastore. It changes the order to completed by storing completed order details in the Order file datastore.

"5.0 Manage customers and orders" is a process that allows the Manager entity to read and modify the data in the Customer file and Order file datastores. It sends/receives Customer data and Order data to/from the Manager and handles the interaction with the datastores via Customer details and order details data flows.