Process Modeling: Context and Data Flow Diagrams
MIS 374 Rev 02
Process Modeling: Context Diagrams and Data Flow Diagrams (DFDs)
Introduction
Figuring out the business processes for complex systems can be complicated. For example, if the goal is to streamline an existing supply chain process, your investigation will cross multiple business units, perhaps starting with an on-line order, a retail store pick-up, or a telephone order. How does the current process work to replace items in inventory storage and on retail shelves? Computer systems make these processes faster, but often increase complexity. As a business analyst, programmer analyst, or IT auditor you are likely to need a graphical technique to help investigate and document current processes and work with a team to determine where problems occur and what the best solution is. Graphical process models are a common part of Root Cause analysis to determine exactly where problems occur. Graphics help teams communicate what software needs to be created or fixed based on a view of what data must be processed to meet and fulfill system requirements.
Description
A data flow diagram (DFD) is a drawing that shows how a system's environmental entities, processes, and data are interconnected. Using four simple symbols users can show developers their current system processes and what they would like to change. The only four symbols are shown in Table 1 below.
Table 1. Data Flow Diagram Symbols
A square is an Environmental Entity (EE)—a source of, or destination for, data outside the system. An arrow is a data flow. Each data flow must have a unique identifier.
A process bubble is a process that changes data. Process bubbles should be numbered at the top. The Process Label should be in a verb – object format. The bottom section identifies an actor or system component.
An open rectangle is a data store. unnumbered process bubble in the shape of a circle to represent the entire system. Figure 1 shows the context diagram for the initial investigation
Process Modeling: Context Diagrams and Data Flow Diagrams (DFDs)
Introduction
Figuring out the business processes for complex systems can be complicated. For example, if the goal is to streamline an existing supply chain process, your investigation will cross multiple business units, perhaps starting with an on-line order, a retail store pick-up, or a telephone order. How does the current process work to replace items in inventory storage and on retail shelves? Computer systems make these processes faster, but often increase complexity. As a business analyst, programmer analyst, or IT auditor you are likely to need a graphical technique to help investigate and document current processes and work with a team to determine where problems occur and what the best solution is. Graphical process models are a common part of Root Cause analysis to determine exactly where problems occur. Graphics help teams communicate what software needs to be created or fixed based on a view of what data must be processed to meet and fulfill system requirements.
Description
A data flow diagram (DFD) is a drawing that shows how a system's environmental entities, processes, and data are interconnected. Using four simple symbols users can show developers their current system processes and what they would like to change. The only four symbols are shown in Table 1 below.
Table 1. Data Flow Diagram Symbols
A square is an Environmental Entity (EE)—a source of, or destination for, data outside the system. An arrow is a data flow. Each data flow must have a unique identifier.
A process bubble is a process that changes data. Process bubbles should be numbered at the top. The Process Label should be in a verb – object format. The bottom section identifies an actor or system component.
An open rectangle is a data store. unnumbered process bubble in the shape of a circle to represent the entire system. Figure 1 shows the context diagram for the initial investigation