8.6 Defining a Variable in the Data Model with Rule Author

Rule Author lets you use variables in the data model. When you use a variable, this allows you to use figurative constants in rules. For example, the data model for the SOA Order Booking application includes a variable named AUTOMATED_ORDER_LIMIT that specifies the business policies for the order price limit that can be approved without a manual credit approval. The SOA Order Booking application rules use a variable to define a figurative constant that defines the policies for an order value, where a value above the specified limit requires manual credit approval.

8.6.1 How to Define a Business Rules Variable in the Data Model

Use the Rule Author Definitions tab to add a variable to the data model. For example, in the SOA Order Booking application, we use Rule Author to add the AUTOMATED_ORDER_LIMIT variable to the data model.

To add a variable to the data model:

1. Click the Definitions tab (using the OrderBookingRules dictionary).

2. In the navigation tree, click the Variable node. This shows the Variable Summary page.

3. If you have not previously defined the AUTOMATED_ORDER_LIMIT variable, then click Create. This shows the Variable page.

4. On the Variable page, in the Name field, enter AUTOMATED_ORDER_LIMIT.

5. In the Alias field, enter AUTOMATED_ORDER_LIMIT.

6. Select the Final check box (by default this check box is selected).

7. In the Type box, select float

8. In the Expression box, enter 1000.00.

   To use the define expression Wizard to assist you when you create an expression, click the edit icon.

9. Click OK (see Figure 8-10).

   
   

   Note: When Rule Author creates a variable, it adds a "DM." to the name you enter in the Name field (DM stands for Data Model).

   
   

   Figure 8-10 Rule Author Variable Definition Page

   
   Description of "Figure 8-10 Rule Author Variable Definition Page"