Session 10 Flashcards
What are the contemporary Methods for Determining System Requirement?
JAD: Joint Application Design
Prototyping
What is an example of Process Modeling?
Data Flow Diagrams (DFD)
Which standard of Data Flow Diagram do we use? Gane and Sarson or Demarco and Yourdon?
Gane & Sarson
What is different about the Gane and Sarson Symbols?
They have a shaded area for identifiers
Whats a data flow?
Red Arrow
data in motion
Whats a data store?
Data at rest
rectangle with shaded area
Whats a process?
work/actions performed on data = transformed, stored, distributed
Rounded square with shaded area
What’s a source/sink?
Origin/destination of data
Blank rectangle
What’s the decomposition of DFD?
Context Diagram
Level-0
Level-1
…
Primitive DFD
What is the context diagram?
The highest level view of the system
Contains only one process
What is the level-0 diagram?
Represents a system’s major processes, data flows, and data stores at a high level of detail
Same sources/sinks with context diagram
True of False: Input and Outputs of a process must be different.
True
True or False: Objects on a DFD can have the same name
False
T or F: A process can only have input/outputs respectively
False, a process must have both an input and an output
T or F: Data must be moved by a process when moving from one data store to another.
True
T or F: Data can be moved from an outside source to a data store.
False, it must be moved by a process
T or F: Data can’t move from a data store to an outside source
True, it must be moved by a process
Can data move from a source to a sink?
No, it must be moved by a process
Can data flow in both directions with the use of one arrow?
No, it must be represented by two arrows, representing a read before an update.
T or F: Data flows cannot be forked or joined
True
T or F: A data flow cannot circle back to the same process it leaves
True
