MBI630: Class 5 6/10/2016 Process Modeling and Data Flow Diagrams (Supplemental)

MBI630: Class 5 6/10/ types of Models Logical models show what a system ‘is’ or ‘does’. They are implementation-independent; that is, they depict the system independent of any technical implementation. As such, logical models illustrate the essence of the system. Popular synonyms include essential model, conceptual model, and business model. Physical models show not only what a system ‘is’ or ‘does’, but also how the system is physically and technically implemented. They are implementation-dependent because they reflect technology choices, and the limitations of those technology choices. Synonyms include implementation model and technical model

MBI630: Class 5 6/10/ types of Models (cont.) As-Is (Current System) To-Be (Future System) To build ”To-Be” model we try to formalize problems of “As-Is” model and propose the solutions to those problems. The result of such work is the “To-Be” model. Note that “To-Be” model is our vision of the ideal future.

MBI630: Class 5 6/10/2016 Common Mechanical Errors

MBI630: Class 5 6/10/2016 Illegal Data Flows

MBI630: Class 5 6/10/2016 Logical Processes Logical processes are work or actions that must be performed no matter how you implement the system. –Even for the future system, at the definition phase, the process model should be logical. In the study phase, the current system was analyzed in three levels of models: –Context Diagram –System Diagram (Level 0) –Event Diagrams (Level 1, level 2, …)

MBI630: Class 5 6/10/2016 Context Diagram

MBI630: Class 5 6/10/2016 System Diagram

MBI630: Class 5 6/10/2016 Event (Child) Diagram(s)

MBI630: Class 5 6/10/2016 How to Model a New System Step 1: Identify the changes in functional requirements for the new system Step 2: Establish the context for the new system Step 3: Create a new system diagram Step 4: Create necessary child diagrams

MBI630: Class 5 6/10/2016 Identify the changes in functional requirements for the new system Source: Problem Statement (Cause/Effect) Prioritize the “System Objectives” based on the urgency/importance of the effects Regroup the objectives into changes in functional requirements e.g., –Operational requirements, –Reporting/Inquiry requirements

MBI630: Class 5 6/10/2016

MBI630: Class 5 6/10/2016 Establish the context for the new system Analyze the new functional requirements in terms of necessary input/output of data i.e., Is there any new input? Is it necessary to produce new output? Is it going to allow new functions to external entities?

MBI630: Class 5 6/10/2016 New Context Diagram

MBI630: Class 5 6/10/2016 Create a new system diagram Principles for creating new DFD –Keep the model simple –Try to use data stores to connect all the processes Identify the functions that must be affected by the new functional requirements Add necessary data stores Determine the boundary of the new system

MBI630: Class 5 6/10/2016 New System Diagram

MBI630: Class 5 6/10/2016 Create necessary child diagrams Explode each function to depict the flow of data within the function A list of events within the function will be helpful

MBI630: Class 5 6/10/2016 A New Event (Child) Diagram