4.1 Setting a binary value

This chapter discusses typical design considerations when designing and implementing a binary decision using Blueriq.

When modeling a decision that is limited to two values (for instance Boolean), there are multiple possibilities to achieve this:

Using a constant value and a business rule
Using two business rules
Using a decision table

1. Constant value combined with business rule

2. Two business rules

3. Decision table

It is tempting to skip the column for male, but it is strongly advised to model a complete table.

It is perhaps even more tempting to skip the [ ]-column for ELSE, but it is also strongly advised to model an ELSE-column whenever the values are not restricted by a value list.

If Applicant.Gender was in fact limited by a value list consisting of the values Male and Female and it is obvious the set will never expend, the ELSE-column would have been otiose.

What to use?

The choice of method is often based on the preference of the business engineer. General recommendations are listed below:

Whenever the result depends on multiple input values, it is best to use a decision table.
Whenever the result is a calculation, it is best to use a form with a business rule.
It is recommended to formally decide which method to use and capture that in an architecture document. A consistent use of a style throughout a project will help the maintainability of a project. There are many roads that lead to Rome, but within one project it is best if all business engineers follow the same road.