Salesforce App Builder Practice Exam

In an external lookup relationship, the parent can only be an external object. This relationship is specifically designed to link an external object to a Salesforce object, allowing you to integrate data from an external source within Salesforce. By ensuring that the parent is an external object, Salesforce maintains the integrity and compatibility necessary for managing connections to outside data sources, such as databases or systems that store information not native to Salesforce.

While standard and custom objects can establish other types of relationships (like lookup and master-detail relationships), they cannot serve as parents in this particular scenario. The distinct nature of external lookup relationships is essential for scenarios where data integration is required, and it distinguishes them from standard relationships found in Salesforce. Thus, external lookup relationships are focused specifically on providing connections to external data, reinforcing the understanding of their purpose within the Salesforce landscape.