1. MAPPING DATA FLOW DIAGRAMS INTO STRUCTURE CHARTS
Transform and Transaction Analysis

2. Requirements
System Design
Detailed Design
Implementation
Installation & Testing
Maintenance

3. Goals and Concepts of Structured Analysis and Design:
structured development of software:
methodology
notation (DFD, SC)
integration of analysis and design
quality control (cohesion, coupling)
based on the flow of information (data)
provides proven heuristics

4. The Focus is the Mapping
prepare and analyse a
Data Flow Diagram - DFD
prepare and check
a Structure Chart - SC

5. Design ...
... is an activity concerned with making major decisions, often of a structural nature.
... builds coherent, well planned representations of programs that concentrate on the interrelationship of parts at the higher level ...
[P. Freeman]

6. Structured Analysis and Design Information Flow Analysis
1 - specify the flow of information in your system
=> DFD
2 - identify typical structural patterns in the DFD
=> analysed & annotated DFD
3 - use a proven heuristic to map DFD into SC
=> first SC
4 - refine and check your Structure Chart
=> final SC

7. Two Major Structural Patterns - Two Major Alternatives :
Transform (Flow) Analysis
Transaction (Flow) Analysis

8. center of transformation
Transform Flow:
input-driven
center of transformation
output-driven

9. Transform Flow Characteristics
the system has a single, coherent objective
transformation center executes algorithms, data transformation, database manipulation, ...
input-driven processes filter, check and translate external data flows
output-driven processes format results for presentation to the environment (user)
multiple paths to obtain input

10. Transform Analysis: mapping heuristic
ct1 i2
ct2 o3
sys
I-ctrl
P-crtl
O-ctrl i1 i2
ct1
ct2 o1 o2 o3

11. Transaction Flow: action-path T reception-path T ... transaction
center

12. Transaction Flow Characteristics
single line of reception processes
transaction: a single data item that includes all necessary information for execution
transaction center evaluates transaction & initialises correct action-path => distribution
action-paths implement (clearly) different types of functionality => execution
an action-path could be a complete
(sub-)system with transform flow characteristics

13. Transaction Analysis: mapping heuristic
sys r2 r2
trc r1
trc s1 s2 i1 i2 i1
cot o1
cot i2 o1

14. Transaction Analysis may include Transform Analysis as an element.

15. Transform Analysis as element of Transaction Analysis r1 sys r2 r2 trc
cot o1
cot i2 o1

16. End of Section 3d
coming up:
more about
transform analysis