My case is like following:
1. user selects a feature.
2. user creates a new row in the feature's relate table
3. An Arcade attribute rule in the relate table will get the selected feature's ID and assign the ID to the newly created row.
Not sure if this can be done since two $feature variables needed. have not see a sample which updates a table.
Note: database is Oracle/SDE. Table is registered with SDE so it has OID.
Thanks...