LO5 5.2 Data flow diagrams Flashcards
1
Q
External entity
A
rectangle with sharp corner
-where data comes from = sources
- sink= where the data goes to
-
2
Q
Process
A
rectangle with smooth edges
-ways in which the data in system is collated
3
Q
Data store
A
4
Q
Data flow
A
arrow
-flows of data between entities and the processes
5
Q
Level 0 DFD
A
-simple diagrams to show how data flows
-do not have storage of data
6
Q
Level 1 DFD
A
-have storage of data
-more complex
7
Q
Rules for drawing level 1 DFD
A
-data only flows in one direction
-data flow connects to at least one process
-every data flow is labelled
-at least one input or output for each external entity
8
Q
impacts affecting the flow of information
A
information characteristics
human error
communication breakdown
hardware failure
