In ServiceNow, domain separation allows for the partitioning of data, processes, and administrative tasks into distinct domains within the same instance. When it comes to business rules, if a business rule exists in the parent domain and another non-overriding business rule exists in the child domain, both rules will be executed for the child domain1.

This behavior is part of the domain hierarchy logic, where the child domain inherits the properties and rules of its parent unless explicitly overridden. Since the business rule in the child domain is non-overriding, it does not cancel or replace the parent domain’s rule. Instead, it adds to the logic that will be processed when the conditions for the business rule are met.

Therefore, when an action occurs that triggers the business rules, the system will first run the business rule from the parent domain followed by the business rule from the child domain. This ensures that the foundational logic set by the parent domain is always applied, while still allowing for additional, domain-specific customizations in the child domains2.

It’s important to note that this behavior can be controlled and configured according to the needs of the organization, and understanding the implications of domain inheritance is crucial for proper domain separation management in ServiceNow3.