A Decision table represents conditions and the respective actions to be taken to address them, in a structured tabular format.
It is a powerful tool to debug and prevent errors. It helps group similar information into a single table and then by combining tables it delivers easy and convenient decision-making.
To create the decision table, the developer must follow basic four steps:
● Identify all possible conditions to be addressed
● Determine actions for all identified conditions
● Create Maximum possible rules
● Define action for each rule
Decision Tables should be verified by end-users and can lately be simplified by eliminating duplicate rules and actions.
Let us take a simple example of day-to-day problem with our Internet connectivity. We begin by identifying all problems that can arise while starting the internet and their respective possible solutions.
We list all possible problems under column conditions and the prospective actions under column Actions.
|
Conditions/Actions |
Rules |
|||||||
Conditions |
Shows Connected |
N |
N |
N |
N |
Y |
Y |
Y |
Y |
Ping is Working |
N |
N |
Y |
Y |
N |
N |
Y |
Y |
|
Opens Website |
Y |
N |
Y |
N |
Y |
N |
Y |
N |
|
Actions |
Check network cable |
X |
|
|
|
|
|
|
|
Check internet router |
X |
|
|
|
X |
X |
X |
|
|
Restart Web Browser |
|
|
|
|
|
|
X |
|
|
Contact Service provider |
|
X |
X |
X |
X |
X |
X |
|
|
Do no action |
|
|
|
|
|
|
|
|
Table : Decision Table – In-house Internet Troubleshooting