When enabling attachments for a particular geodatabase feature class, a relationship class is automatically created to maintain the link between each feature and its associated attachment stored in the attachments table. In the event the relationship class is inadvertently deleted, it is not possible to simply build a relationship class between the attachments table and its feature class, while re-enabling the attachment's functionality. Therefore, a workflow is required to re-establish the relationship as well as enable attachments, so that attachments can be added and existing attachments accessed via the Attachment Manager.
This article provides instructions to enable and re-establish the relationships between the geodatabase feature classes and its related attachments.
Note: The copied feature class is renamed with '_1' at the end of the name.
Note: The _1_ATTACH table along with a new relationship class is automatically created.