This document discusses decision points and decision tables. It defines a decision point as a combination of one or more conditions that define various possibilities in a system's behavior. It provides examples of decision tables to test different conditions, using 1s to represent true and 0s to represent false. It explains that an OR operator results in true if either condition is true, while AND requires both conditions to be true. Finally, it shows that a combined decision with no brackets is evaluated as AND before OR.

1. Decision points

2. IF amount
>1000 THEN
assess by
supervisor
IF not in
stock THEN
order
IF number of
books > 8 OR
sum ≥ 100
THEN extra
discount
A decision point is a a combination of one or more conditions
that define the conditions for the various possibilities in the
subsequent system behaviour.

3. IF number of
books > 8
THEN extra
discount

4. IF number of
books > 8
THEN extra
discount
Test situations
Number of books
Result

5. Test situations 1 2
Number of books >8 ≤8
Result true false
IF number of
books > 8
THEN extra
discount
Singular conditions lead to
2 test situations

6. Test situations 1 2
Number of books >8 ≤8
Result 1 0
IF number of
books > 8
THEN extra
discount
In Boolean algebra a “1” is
used to represent “true”

7. Test situations 1 2
Number of books >8 ≤8
Result 1 0
IF number of
books > 8
THEN extra
discount
In Boolean algebra a “0” is
used to represent “false”

8. Decision points may consist
of a combination of
conditions
IF number of
books > 8
OR
sum ≥ 100
THEN extra
discount
IF number of
books > 8
THEN extra
discount

9. A B
IF number of books > 8 OR sum ≥ 100 THEN extra discount

10. IF number of books > 8 OR sum ≥ 100 THEN extra discount
Abbreviated notation
A OR B

11. IF number of books > 8 AND sum ≥ 100 THEN extra
discount
IF number of books > 8 OR sum ≥ 100 THEN extra discount
Abbreviated notation
A OR B
Abbreviated notation
A AND B

12. Complete
decision table
A B
1 1
1 0
0 1
0 0
Based on two conditions we
get these possible
combinations

13. A B
1 1
1 0
0 1
0 0
The end result depends on
the operators AND and OR

14. Truth table
A B A OR B
1 1 1
1 0 1
0 1 1
0 0 0
With the operator OR the end
result is ONLY false when
both conditions are false
This table shows the outcome
of all situations of a full
decision tale. Such a table is
called a truth table.

15. Truth table
A B A AND B
1 1 1
1 0 0
0 1 0
0 0 0
Truth table
A B A OR B
1 1 1
1 0 1
0 1 1
0 0 0
With the operator AND the
end result is ONLY true when
both conditions are true

16. Truth table
A B C (A AND B) OR C
1 1 1 1
1 1 0 1
1 0 1 1
1 0 0 0
0 1 1 1
0 1 0 0
0 0 1 1
0 0 0 0
A combined decisionthere
may be different operators.
When there are no brackets
AND proceeds OR