If a utility pole is deleted and all its associated transformers must also be deleted, which type of association should be used?

In a scenario where the deletion of a utility pole requires the deletion of all associated transformers, a relationship class is the most appropriate option. A relationship class in a geodatabase is designed to manage the relationships between feature classes and allows for the establishment of rules regarding how features are related. In this case, it ensures that if the utility pole is deleted, all related transformers are also deleted automatically due to the defined relationship rules.

This type of relationship supports cascading deletions, which is crucial for maintaining data integrity. The relationship class can specify that the transformer features depend on the utility pole, meaning the lifecycle of the transformers is directly tied to the utility pole. This automated process minimizes the risk of orphaned records (transformers without their associated pole) and ensures that updates to the main feature propagate correctly.

Other options, such as joins or spatial joins, are primarily used for querying and analyzing data rather than managing the lifecycle and dependencies of features in a geodatabase. Joins would not inherently manage deletions, and relates do not enforce dependency rules, making them unsuitable for this scenario. Thus, the relationship class is the correct mechanism to facilitate this kind of data management.