Data Flow Diagrams - Essay Example

The data flow diagrams is a modelling technique that allows use of pictures to convey how information data flows through the systems connected by pipelines of data (Thomas Hathaway, 2015). The flow of information shows the source and the destination of the data.

They are different types of symbol sets that are used depending on the profession, the most common sets are Gane and Sarson symbol sets and Yourdon symbol sets. To create better and more understandable flowchart the following simple guidelines must be adhered to;

• Naming conventions must always be taken care of with processes using strong verbs and dataflow, datastore, and external entities using nouns.
• A minimum of one input and output of dataflow in each process of a DFD.
• A DFD must have a maximum of 7 - 9 processes.
• Dataflow must begin and end with a process and not splitting
• The external entities must be marked on the right-hand top corner with a diagonal line.
• A process is used to communicate logical departments in an organization and looping of the process is not allowed.
• Data stored and flowing in a system must go through a system.
• Always use the sandwich rule to connect input and output processes and the symbols must be standard and appropriate.
• For clarification in DFD use comments and annotated descriptions.

Some of the standard symbols are

                                    Input or output                                                                    Document

                                        The computer processes                                                            Data flow

Complex DFD is done through a process called decomposing, modeling hierarchy, or leveling; this process of leveling is a series of detailing diagrams until all the primitive functions are properly identified. When DFD fits on a single window is known as level 1 DFD. Level 2 is a DFD that expands the level 1 or top-level. All the levels below are level 3, level 3, and so on. A level that cannot be further decomposed is called the bottom-level process (Systems Analysis and Design, n.d.).

Flowchart assists the auditors and accountants in analyzing the current system of the organization for the control loopholes and weaknesses ants reporting the same to the management. This assists the auditors in defining the audit trail, following it up and finally evaluating the system. Further, it assists in the assessment of the control risk of the company.

The system analyst uses flowcharts to show how the information flows in an organization environment, thus each department is evaluated the data received and sent and makes sure only the valid and necessary data is exchanged.

A computer programmer uses both pseudocode and flowcharts to design programs in that they use it to design the systems flowchart.

A security expert managing internal data uses the DFD in identifying the weakness in internal data control and looking for ways to improve by indicating new systems in an organization.

A system designer uses DFD in improving the existing system or overhauling the existing system by replacing it.