Define top-down approach as it relates to drawing data flow diagrams
Introduction
Understanding of how data flows is essential for a analyst to be able to plan and implement functions in an organization. The top-down approach provides a useful way of understanding how the data flows. According to Anderson and Yull (2002), using the top-down approach in data flow diagrams provides a more in-depth analysis of the system. Kendall and Kendall (2011) indicate that the data flow diagram moves from general to specific. This implies that the more the levels the more details and more complex a system.
A top down approach in data flow diagrams offers several significant advantages. According to Kendall and Kendall (2011), using a top-down approach prevents the development of confusion. This is when all the data is used to develop the data flow diagram. It provides a way of organizing data in a logical manner. Further, data flow diagrams can be complex in nature and will require planning and the implementation of a data flow diagram becomes easier when using the top down approach. Additionally, the top-down approach can be time saving. It allows different data systems to be analyzed concurrently. Kendall and Kendall (2011) also note that the top-down approach helps to prevent analysts from being caught in difficult situations, which may prevent them to analyze the system accurately. This is commonly associated with the bottom-up approach.
Conclusion
Implementation of the top down approach is effective for complex systems. It makes it easier for the analysts to understand the different levels of the system contribute to the overall function of the system. Further, it is recommended to adopt the top-down approach as it offers significant advantages that have been discussed above.
What is the difference between a logical and physical data flow diagram?
Introduction
Data flow diagrams can be classified as either logical or physical data flow diagrams (Kendall and Kendall, 2011). Logical data flow diagrams are designed to indicate how a business functions (Kendall and Kendall, 2011). This implies that in a logical data flow diagram, there will be the presence of the various business operations and the required data for these operations. A physical data flow diagram is more detailed than a logical data flow diagram. It shows the implementation of a system. This will include the hardware, files, software, and the people that will be involved in running the system (Kendall and Kendall, 2011).
The logical data flow diagram makes it easier to understand a system in a business. The physical data flow diagram indicates how the various functions are achieved using technology. The logical data flow diagrams usually do not have any form of process descriptions on how certain functions are done. However, in a physical data flow diagram there is a description of the specific technology used. This may include the physical devices, which include input and output devices such as servers, printers, scanners, and bar code readers. The physical data flow diagrams are more complex than the logical data flow diagrams as they contain more data stores (Kendall and Kendall, 2011). The logical data flow diagrams present a more stable system as compared to the physical data flow diagrams. This is because the entries used in the logical system can be operated despite the form of the physical means applied.
Conclusion
The physical data flow diagram is normally complex and cannot be used to communicate with employees. On the other hand, the logical data flow diagram is simple hence can be used to communicate effectively with the employees (Kendall and Kendall, 2011). Additionally, since the logical data flow diagram mainly focuses on the business activities, many users can easily communicate using it. In case of problems in a system, it can be easier to use the physical data flow diagram to address the problems, as it is more specific and detailed.
List five characteristics found on a physical data flow diagram that are not on a logical data flow diagram
Introduction
The different features of both the logical and physical data flow diagrams make them have a variety of different outcomes when used. The features of the physical data flow diagram make it have several advantages that are beneficial to the system of the business (Kendall and Kendall, 2011).
Using a physical data flow diagram makes it easier to know processes that are automated and processes that are manual. Further, the physical data flow diagram has controls that used to ensure processes operate accurately (Kendall and Kendall, 2011). Unlike the logical data flow diagram, the physical data flow diagram has temporary data stores and transaction files (Kendall and Kendall, 2011). Furthermore, the physical data flow diagrams utilize a sequencing procedure, which ensures that all processes are done in a specific order (Kendall and Kendall, 2011). Another characteristic of the physical data flow diagram is that it specifies actual names of printouts and files in the system (Kendall and Kendall, 2011).
Conclusion
Each of the features described above makes the physical data flow diagram significant in running the system in a business.
References
Anderson, Howard, and Sharon Yull. BTEC nationals - IT practitioners: core units for computing and IT. Oxford: Butterworth-Heinemann, 2002. Print.
Kendall, K. E., & Kendall, J. E. (2011). Systems Analysis and Design (8th Ed.). Upper Saddle
River, N.J.: Pearson/Prentice Hall.
