How can an ArcGIS Pro analyst ensure a feature layer and a stand-alone table are published together?

Creating a relationship class between the feature layer and the stand-alone table is the correct approach to ensure that the two datasets are treated as related entities when published. A relationship class defines a connection between two tables or feature classes in a geodatabase, which allows for the establishment of meaningful associations between the data in those tables or layers. This relationship ensures that when the feature layer is published, the associated stand-alone table is also recognized and included in the publication, maintaining the integrity and usability of the data for end-users.

In contrast, the other methods suggested do not guarantee that the relationship will be preserved in a published map service. An in-memory relate or a temporary join exists only within an ArcGIS Pro session and would not be recognized outside that context after publication. Copying data to a file geodatabase and compressing to a zipfile might package the data together, but it does not create a formal link between the table and the feature layer, making it less effective in maintaining their relationship over a published service. Therefore, the creation of a relationship class is the most robust method for ensuring that both datasets are published together with their defined associations intact.