Please enable JavaScript.
Coggle requires JavaScript to display documents.
SAD: MODULE 3 (CHAPTER 7) [STRUCTURING SYSTEM PROCESS REQUIREMENTS]…
SAD: MODULE 3 (CHAPTER 7)
[STRUCTURING SYSTEM PROCESS REQUIREMENTS]
DEFINITIONS & SYMBOLS
Process
work/actions
Work or actions performed in data (inside the system)
Data Store
Data at rest (inside the system)
Source/sink
External entity that is the origin or destination of data (outside the system)
Data Flow
Arrows depicting movement of data
Context Diagram
Overview of an organizational system that shows
boundaries
the system boundaries
interact
external entities that interact with the system
major
major info flows between the external entities and the system
Level-0 diagram
high level
A data flow diagram that represents a system's major processes, data flows, and data stores at a high level detail
DECOMPOSITION OF DVDs
Functional Decomposition
iterative/finer finer
An iterative process of breaking a system description down into finer and finer detail
Balancing DFDs
Conservative Principle
conserve
Conserve inputs and outputs to a process at the next level of decomposition
Balancing
Conservation of inputs and outputs to a data flow diagram process when that process is decomposed to a lower level
Data Flow Splitting
split/different
Composite data flow at a higher level is split and different parts go to different processes in the lower level DFD.
Guidelines for Drawing DFDs
Completeness
Consistency
Timing
time not represented well on DFDs
Iterative Development
