null
US
Sign In
Sign Up for Free
Sign Up
We have detected that Javascript is not enabled in your browser. The dynamic nature of our site means that Javascript must be enabled to function properly. Please read our
terms and conditions
for more information.
Next up
Copy and Edit
You need to log in to complete this action!
Register for Free
84699
DFD Basics
Description
Systems Analysis & Design (Data Flow Diagrams) Mind Map on DFD Basics, created by callumh93 on 12/05/2013.
No tags specified
data flow diagrams
systems analysis & design
systems analysis & design
data flow diagrams
Mind Map by
callumh93
, updated more than 1 year ago
More
Less
Created by
callumh93
over 11 years ago
70
0
0
Resource summary
DFD Basics
Graphical representation of the flow of data throughout a system
shows what kinds of information will be input to and output from the system
Also shows where data will come from and go to, and where the data will be stored
does not show information about the timing, or about whether processes will operate in sequence or in parallel
common practice to draw the context-level data flow diagram first
shows the interaction between the system and external agents which act as data sources
context diagram shows the entire system as a single process, and gives no clues as to its internal organization
Context Level DFD
no inside workings of the process are detailed
Level 1 DFD that shows some of the detail of the system being modeled
shows how the system is divided into sub-systems (processes)
Every process detailed on the level 0 diagram has a level 1 diagram
Must be balanced - i.e. show same input/output flows & data stores as detailed in level 0 DFD
Data flow diagrams can be used in both Analysis and Design phase of SDLC.
Gane and Sarson Elements
Process - has a number, name, description, at least one output flow, at least one input flow
Data flow arrow - has a name, one or more connections to a process
Data store - has a number, name, description, 1 or more output flows, 1 or more input flows
External entity - has a name and description
Level 0 DFD
Shows all processes, data stores,external entities, and data flows amongst them
Purpose is to show major high level processes that are interrelated
Overview of the system
Level 2 DFD
Shows a level 1 DFD in more detail
Again has to be balanced by showing the same input/output flows & data stores as the level 1 equivalent
Numbering at this level has two decimal points e.g. 1.2.4
Show full summary
Hide full summary
Want to create your own
Mind Maps
for
free
with GoConqr?
Learn more
.
Similar
Game and Sarson Symbols
callumh93
Data Flow Diagrams
Lilli Flahh
Data Normalisation Basics
callumh93
How to normalise logical data models
callumh93
Relational Algebra
callumh93
Data Flow Diagrams
P McIvor
GCSE Chemistry C1 - Carbon Chemistry ATOMS, MOLECULES AND COMPOUNDS (Easy)
T W
MCAT Study Plan
Alice McClean
TOEFL English Vocab (A - M)
Ali Kane
Physical Description
Mónica Rodríguez
Specific topic 7.6 Timber (processes)
T Andrews
Browse Library