Which steps are necessary to set up a '1-to-many' data relationship for a customer class?

To establish a '1-to-many' data relationship for a customer class, defining an Association rule on the customer class is crucial. This rule allows you to specify how the customer class relates to other classes, effectively facilitating a structured interaction between the instances of the customer and other related entities. By defining this association, you are explicitly indicating that one instance of the customer can be linked to multiple instances of another entity, which is the essence of a '1-to-many' relationship.

This step is foundational, as it integrates the relationship within the Pega platform, enabling the system to understand and manage the data interactions appropriately. The Association rule effectively acts as a bridge, guiding how data retrieval and interactions are to be carried out between the customer class and its related entities.

While other options may contribute to the overall data relationship structure, such as creating a 'Page List' property or defining primary key-foreign key relationships, the Association rule is specifically designed to articulate and manage these relationships within the Pega context, making it the most direct and relevant choice for setting up a '1-to-many' data relationship.