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
Constant value combined with business rule
Two business rules
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.