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Chapter 4

ITM 410 Chapter Notes - Chapter 4: Flowchart, Data Flow Diagram, Business Process

Information Technology Management
Course Code
ITM 410
Margaret Plaza

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Chapter 4 – Documenting Information Systems
Reading System Documentation
- There are two types of system documentation
oData flow diagram and system flowcharts
- Data flow Diagram
oData flow Diagram: Is a graphical representation of a system
it shows the system components, data flows, sources, destinations and
storage of data
- Context Diagram (Overview) – pg 105
oContext Diagram: is a top-level or a detailed, diagram of the system depicting
the system and all its activities as a single bubble and showing data flows into
and out of the system and into and out of the external entities
External entries: are entities (person, place or thing) outside the system
that send data(bank) to, or receive data (customer) from the system
- Physical Data Flow Diagram –pg 106
oPhysical Data Flow Diagram: is a graphical representation of a system showing
the system internal and external entities and the flows of data into and out of
these entities
oInternal Entities: is an entity within the system that transforms data
Ex. Clerks (person), department (place), computer (thing)
oIt specifies where, how and who and it didn’t tell us what activities are being
- Logical Data Flow Diagram – pg 107
oLogical Data Flow Diagram: is a graphical representation of the system
showing the system’s process, data stores, and the flows of data into and out of
the processes and data stores
It looks at what the system is performing and not where, how and who
It looks at the activities that a system performs
The diagram is also known as “level 0” diagram
- When both DFDs have the same external entities, it is known as balanced
- The successive subdividing or “exploding” of logical DFDs are called top-down
Reading System Flowcharts
-System Flowcharts: is a graphical representation of a business process, including
information process (input, data processing, data storage, and output), as well as the
related operations processes (people, equipment, organization, and work activities)
- The system flowchart presents a logical and physical rendering of the who, what, how
and where of information and operations processes
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