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Logical Data Flow Diagrams

19 January, 2016 - 12:35

Our first view of the process is a general one. Figure 11.5 portrays the M/S process in the form of a context diagram. Recall that a context diagram defines our area of interest. Although it presents an abstract view of the process, it serves the purpose of delineating the domain of our study. In Figure 11.5, one input enters the process and seven outputs emerge. Also, notice the entities in the relevant environment with which the M/S process interacts. Some of these entities reside outside the organization (Customer and Carrier), whereas some are internal to the organization but external to the M/S process (payroll process and revenue collection process.)1 These internal entities are covered in detail in subsequent chapters.

Figure 11.5 The M/S Process—Context Diagram 

Figure 11.6 presents a level 0 diagram of the M/S process. Observe that the inputs and outputs are identical to those presented in Figure 11.5. As you recall, this balancingof inputs and outputs is an important convention to observe when constructing a set of data flow diagrams. The single bubble in Figure 11.5 has been divided into three bubbles in Figure 11.6, one for each of the three major functions performed by the M/S process. 2 Additional data flows connecting the newly partitioned bubbles appear, as do the data stores used to store various sets of data.3

Review Question

What are the three major processes? What are the subsidiary processes of each major process?

The physical means used to disseminate the order may vary from using a paper sales order form to using computer screen images as illustrated in Figure 11.7. Regardless of the physical form used, we generally expect the dissemination to include the following data flows:

  • A picking ticket authorizes the warehouse to “pick” the goods from the shelf and send them to shipping. The picking ticket identifies the goods to be picked and usually indicates the warehouse location.
  • A packing slip is attached to the outside of a package and identifies the customer and the contents of the package.
  • A customer acknowledgment is sent to the customer to notify him or her of the order’s acceptance and the expected shipment date.
  • A sales order notification is sent to the billing department to notify it of a pending shipment.
  • The bill of lading represents a contract between the shipper and the carrier in which the carrier agrees to transport the goods to the shipper’s customer.

The carrier’s signature on the bill of lading, and/or the customer’s signature on some other form of receipt, substantiates the shipment.

Review Question

What do the terms picking ticket, packingslip, bill of lading,tickler file, and one-forone checkingmean?