Using Collections to Establish a Hierarchy

In many situations, a rule application needs to operate over a hierarchy of data rather than a flat set of related fields. InRule allows you to create relationships between entities to establish a parent-child relationship.

For example, a standard company invoice usually has a set of information that relates to the invoice header such as company name, address, billing contact, etc. In addition, there are a collection of line items that comprise the detail billing section of the invoice. While there are rules that may apply only to the header information or to individual line items, there are also rules that apply to the items as a whole. For example, suppose you wanted a rule that looked at the total amount across all the line items and the customer ID and assigned a discount to the total invoice amount. This can be difficult without the existence of a parent-child structure.