To make sure the pin is recognizable as an input pin, we draw
an arrow inside the pin ( Figure 2.61 ).
At this point we should take a look at the car data from another perspective.
From the fi nding that we need car data arise a few questions: How does the data
get into the system? How will they be updated or removed? The answers to these
questions mean that we found new potential use cases. We will name them add
car data , modify car data , and delete car data .
It is generally a good idea with all kinds of data to take a look at their life-cycles.
Where do they come from and where do they go? There are normally new potential
use cases behind the answers to these questions. The term ??? data ??? is not limited to
software; it also concerns physical things, like liquids or gases, for example.
FIGURE 2-60
Example for input and output pins.
FIGURE 2-61
The object fl ow for ??? start car usage ??? (section).
act Buy soft drink [section]
Check choice
of drinks
Select drink Money
Choice of drinks
[checked] Choice of drinks
[checked]
Output
drink
act Start car usage [section]
[customer not identified]
[customer
identified]
Car
?«essential?»
Identify
customer
Customer
?«essential?»
Check usage
right
Customer
?«precondition?» Car not in use
Usage right
98 CHAPTER 2 The Pragmatic SYSMOD Approach
This is how we proceed step by step.
Pages:
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226