Defining Constraints in Decision Tables

• Constraints are defined in the standard decision table by using the keyword “constraints”
• Constraints are used primarily in the validation engine to check that there are no rules that set (or test) a variable using a value that would break a constraint.
• Constraints specify the allowable values for an attribute
• Constraints on different variables may be grouped in a single decision table, or you can create a separate table for each attribute
• No action is required for validation-only constraints
• Constraints may also be used to specify the behavior when a constraint is broken at execution time
• For execution time constraints just add the the optional “warn” or “stop” actions
• NOTE Only the first rule column is used for the constraints. If there are multiple constraints for an attribute enter them separated by commas

Example

Table DCM03 is a standard decision table containing the business rules. The other table defines some constraints on the values

The validation engine will produce messages like this: