Drawing a hierarchy of flow diagrams. - Modeling of business processes

Drawing a hierarchy of data flow diagrams.

The main task of constructing a hierarchy of DFD-diagrams is to make the description of the modeled domain more clear and understandable at each level of detail. To do this, you should use the "Rule of Seven", according to which you need to select a level of abstraction and detailing of the described process, in which its scheme will consist of no more than seven works, since human possibilities of simultaneous perception and understanding of the scheme of a complex system with many different details and connections do not allow to understand the diagram, where more than six or seven processes are represented. In the event that a detailed description of the process is required, it must be done by decomposing the work of this process. To do this, each or some work of the process is treated as a subprocess and described in a separate scheme of the following level.

In addition, it is not necessary to clutter the diagrams inessential at this level with details, for example, incoming and outgoing flows between functional blocks. Therefore, it is better to decompose workflows in parallel with the decomposition of processes.

The construction of the hierarchy is carried out by sequential execution of the description of the process context diagram, the development of the specification of data structures, the construction of diagrams of the data stream of the zero and subsequent levels, the refinement of the conceptual data model.

As a rule, when building a model of business processes in DFD notation, a context diagram is constructed at the first stage, in the center of which there is a main process connected to receivers and information sources, t.s. reflect documents, requests, messages, with the help of which there is an exchange with entities external to the process described. The number of incoming and outgoing streams on the context diagram should not be large. It is worthwhile to specify them in such a way that after decomposition it could be divided into several streams.

To check the correctness of the composition of the context diagram, a list of events initiating the implementation of the process and arising during the execution of the process is formed.

When developing the specification of data structures, all the structures and elements of each flow are defined, i.e. form a hierarchy of flows. For example, a thread, which is shown by a single arrow in the context diagram, is divided into several threads when it is further detailed. This should be reflected in a hierarchical list.

The construction of diagrams of data flows of zero and subsequent levels begins with the decomposition of the context chart. For each event, a process diagram is generated that is triggered by this event. It is necessary to specify references to the processes with which it is connected by incoming and outgoing streams.

After all these processes are built and decomposed to the required level, you need to build a zero-level diagram (context diagram) again to make sure that the decomposition is done correctly. The specification of structures is checked. If there are discrepancies between the initial context diagram and the diagram created at the end of the simulation, you need to adjust the context chart and the structure specification.

Also We Can Offer!

Other services that we offer

If you don’t see the necessary subject, paper type, or topic in our list of available services and examples, don’t worry! We have a number of other academic disciplines to suit the needs of anyone who visits this website looking for help.

How to ...

We made your life easier with putting together a big number of articles and guidelines on how to plan and write different types of assignments (Essay, Research Paper, Dissertation etc)