Adding the decision logic

The decision logic determines the value of a decision node based on the value of its direct predecessors in the diagram. The decision logic cannot modify the value of other nodes in the diagram.

You can use business rules and decision tables to define the decision logic.

Business rules are conditional statements. Basic business rules use an if-then statement to state what action to perform when specific conditions are met. In the following example, the rule outputs a message encouraging people to stay home if there is a storm alert:

if
     Weather is storm alert 
then
    set decision to "It would be wise to stay home. There is a storm alert." ;

More complex business rules can consist of up to four parts: definitions, if, then, and else.

Decision tables allow you to model complex logic. Their tabular layout helps you effectively document all the possible conditions and results of a decision node. In the following example, the decision table consists of two inputs, the condition columns Rain forecast and Temperature, and an output column, Weather advice. It gives a recommendation on what to bring depending on the weather: a coat, some water, or an umbrella.

You can use input data and the output of subdecisions while defining the logic of a decision node.