Using Collection Functions

When using functions that operate on collections, the first parameter is always a collection. For example, if you want to sum the amount field in a collection of line items, the syntax would appear like the following:

Sum(LineItems, ItemAmount)

Syntax to lookup a data element from a collection:

CollectionLookup(Vehicles, ID, Year=1999 And Make="Ford", "N/A")

Collections are a powerful construct for aggregate and relational rules processing, but they also introduce degrees of complexity that may not be apparent until specific situations call for it. Special functions can be applied to manage a variety of logic scenarios relating to the use of collections - these include @Index, CurrentContext(), and OuterContext().

For a list of available collection functions, please see the Function Reference.