Please note : This help page is not for the latest version of Enterprise Architect. The latest help can be found here.

Define Computation Rules

In a business process, some actions and effects are dependent on the interaction of rules with either another rule or a calculation. For example:

Rule 1) Cars cannot be rented to customers aged under 18 years,  Rule 2) Customers must have a valid driving licence  - Rule 1 must be satisfied before Rule 2 is tested
Rule 4) Penalty of 10% of total rental cost applies to customers with Bad History Level 1 - If the customer has a Bad history Level 1, multiply the rent payable value by 1.1

Access     Diagram | Right-click Rule Task element | Rule Composer > Computation Rule Table

Define a computation rule



See also


In the Project Browser, expand the appropriate business entity Class in the Business Domain model, and drag the attribute that represents the computed action into the Computation Rule Actions field.

Alternatively, you can use Intelli-sense in both the Computation Rule Actions field and the Expression field  to display a list of possible Classes and attributes:

1.Press (Ctrl+Spacebar) in the field to display the list of Classes.
2.Double-click on the required Class, and type . (period) after it; a list of attributes for that Class displays automatically.
3.Double-click on the required attribute.


Create a Business Domain Model


In the Expression field, complete the expression to be evaluated. For example:

If computing Rule 4 above, and you have selected Rent.RentPayable in the Expression field, then type *1.1 immediately after it




In the Rule Bindings field, click on the drop-down arrow and select the number of the rule being modeled (as listed in the Rule table) to link the computation data to the rule.


Add and Remove Rules


If the rule depends on another rule being satisfied first (as for Rule 2 above), type the number of that rule in the Rule Dependency field.




Click on the Save icon in the Rule Composer toolbar to save the computation rule.

If the computation rule is also a Rule Conditions rule, add the condition variable in the Decision table and bind the appropriate rule in the Rule Bind section.

Define Rule Conditions

Bind Rules to Conditions and Actions


Learn more

Learning Center topics

(Alt+F1) | Enterprise Architect | Enterprise Architect | Business Modeling | Business Rules |  Rule Composer
(Alt+F1) | Enterprise Architect | Enterprise Architect | Business Modeling | Business Rules |  Computation Rule Table
(Alt+F1) | Enterprise Architect | Enterprise Architect | Business Modeling | Business Rules |  Rule Composer Example