Chapter 5 Flashcards
Logical Model
Shows what the system must do, regardless of how it will be physically implemented
Physical Model
Describes how the system will be implemented
DFD
Data Flow Diagram: various symbols to show how the system transfers input data into useful information
Gane and Sarson Set
A type of DFD (Data Flow Diagram)
Yourdon
A type of DFD (Data Flow Diagram)
Process
receives input data and produces output that has a different content, form or both.
Business Logic/Business Rules
transforms the data and produces the required results
Black Box
a symbol where all inputs, outputs and general functions of the process are known, but the underlying details and logic of the process are hidden
Data Flow
path for data to move from one part of the information system to another
Spontaneous Generation
all outputs, no inputs
Black Hole
all inputs, no outputs
Gray Hole
the inputs are insufficient to produce the output
data store
represents data that the systems stores because one or more processes need to use the data at a later time
terminators
data origins or final destinations
source
an entity supplying the system with with data
sink
an entity that receives the information
context diagram
top-level view of an information system that shows the system’s boundaries and scope
parent diagram
higher level diagram
child diagram
lower level diagram
Diverging Data Flow
a data flow in which the same data travels to two or more different locations
functional primative
a process that consists of a single function that will not explode further
leveling
process of drawing a series of increasingly detailed diagrams until all functional primitives have been found
Balancing
ensuring all input and output data flows align properly, helps maintain consistance
Exploding
also called leveling, partitioning, or decomposing
