To find the closest date when an attribute was true you use the When Last and When Next functions. These functions look forwards or backwards from a reference date and return a date when a specified boolean attribute is true.
To return the date on which a boolean attribute was last true, looking backwards from a reference date (including the reference date), you use the When Last function. This function has the following syntax:
For example, to determine when a customer's bank balance was last over $100, you would write the following rule in Word:
the date the customer's bank balance was last over $100 = WhenLast(the current date,the customer's bank balance > 100)
To return the date on which a boolean attribute will next be true, looking forwards from a reference date (including the reference date), you use the When Next function. This function has the following syntax:
For example, to determine when was the first time in 2007 that a customer's bank balance was over $100, you would write the following rule in Word:
the date the customer's bank balance was over $100 for the first time in 2007= WhenNext(2007-01-01,the customer's bank balance > 100)
TIP: To see an example of a complete rulebase using this function, open and run the Aged Care Approval rulebase project provided in the Examples folder in the Oracle Policy Modeling installation folder.