From a usage point of view, expressions and business rules add business intelligence to your data. From a technical point of view, they replace static data attributes with dynamic expressions to perform calculations or otherwise manipulate the value of attributes.
You can type an expression as an attribute value for a specific element (or specific elements, if you use multi-select), or as a default attribute value for new elements.
Each expression is evaluated by Focal Point® before it runs to ensure that it meets the expression stringency requirements. If the expression fails the evaluation, none of its operations are completed, and the user must correct the expression according to the feedback that they receive.
An example of a simple expression is to enter =PI instead of 3.1415. Business rules are advanced expressions that you might use to check the quality of your requirements, implement a complete workflow, or aggregate sales figures for a large corporation.
Note To add and manage business rules in Focal Point®, you must be a global administrator or have the global permission business rules.
Expressions are mathematical calculations that provide information; for example, an expression might summarize the attributes in a module or replace a static date field with the current date.
Business rules typically take several parameters and complete more intricate operations. Business rules might cause more actions apart from returning a simple value, such as sending an email notification.
For example, if the Total cost attribute provides the sum of Hardware cost and Software cost attributes, the expression in the Total cost attribute field is = Hardware Cost + Software cost.
The Hardware cost and Software cost attributes are source attributes, and the Total cost attribute is the target attribute. The target attribute detects changes in the source attributes, and updates itself when changes occur. Business rules use a similar structure.
All expressions and business rules are stored in attributes. However, in some cases a business rule might be in a dedicated attribute, separate from the ordinary attributes. For example, a business rule that sends a notification or populates a matrix needs to be in a dedicated business rule container attribute. The container is simply a Text attribute that contains a business rule.
Notes
▪ You can only use one expression or business rule per attribute.
▪ You cannot use the Last Changed By, Last Changed Date, Creator, and Created Date attributes to trigger expressions or business rules.
▪ In business rules such as LinkInfo, and LinkListAttributeSum, if the title of the source link (list, link or incoming link) attribute is changed, the business rule fails.
Example
In this example, the LinkListAttributeSum business rule calculates the sum of an attribute for all of the elements listed in a link, Link List, or Incoming Links attribute. The target element has an attribute called Total resource need, which is the target attribute that is updated whenever a source attribute in the linked source elements changes. The business rule is stored in the Total resource need attribute in the target element. The result of the calculation (90) is visible when the element is displayed.
Expressions can also display images, graphs, and tables. They might also have a special edit mode, for example, in TrafficLight.
