Book a Demo
Prev Next

Compose Business Rules

In modeling your Business Rules, you first define each business rule as a conceptual-level, plain text string within a Business Rule element, and then group the rules by association with Business Task elements. Your next step is to define exactly how the rules operate within the task, setting up the values, conditions, actions and computations that define the actions of a single rule or a combination of rules. For this you use the Rule Composer, with which you transform each conceptual-level business rule statement into a logical level, technology-specific tabulated statement that you can either:

  • Generate code from or
  • Download to a spreadsheet application such as Microsoft Excel, via a CSV file


Context Menu

Browser window or open diagram | Right-click on a Rule Task element | Rule Composer

Rule Composer Tables

The Rule Composer displays as a view in the central work area, divided into three tables.



See also

Rule Statements

The Rule Statements table lists the rules associated with the selected Rule Task; you add a rule to the table by dragging an existing Business Rule element from the Browser window onto an empty row of the table.

You do not create new rules within the table.

Add and Remove Rules


The Decision Table is used to model conditional rules (for example: Cars must not be rented to customers of age less than 18).

The table has three sections:

  • Rule Conditions – to model condition variables
  • Rule Actions – to model action variables
  • Rule Bindings – to link the rule in the rule table
Define Rule Conditions Define Rule Actions Bind Rules to Conditions and Actions

Computation Rule

Using the Computation Rule table, you model rules that require a calculation to be performed on the source information, and/or the interaction of rules.

The table has these columns:

  • Computation Rule Actions
  • Expression
  • Rule Bindings
  • Rule Dependency
Define Computation Rules


  • Business Rule Modeling is available in the Unified Edition and the Ultimate Edition of Enterprise Architect
  • To assist with traceability as you complete the relationships across the Rule Composer, selecting an entry in one table automatically highlights the corresponding rows and columns of the other tables; for example, if a Rule Statement is selected, the related rule column in the Decision Table and row in the Computation Rule table are highlighted
    Similarly, if a Computational Rule is selected, the corresponding column in the Decision Table and row in the Rule Statements list are highlighted
  • If the table columns are not wide enough to display their contents, you can drag the column header margins to increase the width; all tables on the 'Decision Table' tab and the 'Computation Rule' tab are linked, so if you increase the column width on one table it changes the width on all tables
  • The Rule Composer can be opened and the rules logic viewed in the Lite Edition of Enterprise Architect

Learn more