The systems analyst needs to make use of the conceptual freedom afforded by data flow diagrams, which graphically characterize data processes and flows in a business system. In their original state, data flow diagrams depict the broadest possible overview of system inputs, processes, and outputs, which correspond to those of the general systems model discussed… [Continue Reading]
Using Data Flow Diagrams
Data Flow Approach to Human Requirements Determination
When systems analysts attempt to understand the information requirements of users, they must be able to conceptualize how data move through the organization, the processes or transformation that the data undergo, and what the outputs are. Although interviews and the investigation of hard data provide a verbal narrative of the system, a visual depiction can… [Continue Reading]
Developing Data Flow Diagrams (DFDs)
Data flow diagrams can and should be drawn systematically. Table illustrated below summarizes the steps involved in successfully completing data flow diagrams. First, the systems analyst needs to conceptualize data flows from a top-down perspective. To begin a data flow diagram, collapse the organization’s system narrative (or story) into a list with the four categories… [Continue Reading]
Checking the Data Flow Diagrams for Errors
Several common errors made when drawing data flow diagrams are as follows: Forgetting to include a data flow or pointing an arrow in the wrong direction. An example is a drawn process showing all its data flow as either input or output. Each process transforms data and must receive input and produce output. This type… [Continue Reading]
Logical and Physical Data Flow Diagrams
Data flow diagrams are categorized as either logical or physical. A logical data flow diagram focuses on the business and how the business operates. It is not concerned with how the system will be constructed. Instead, it describes the business events that take place and the data required and produced by each event. Conversely, a… [Continue Reading]
