Hi John,
your design of that entity is perfectly ok. No need to create different entities for root and sub organisations for the sole reason of a non-mandatory foreign key, and this should be completely unrelated to what type of delete rule you have.
This is a bug in the "View or Edit Data" functionality of Service Studio. I would suggest you report it to Outsystems as a bug.
this part of the error log is where I think their wrong code is situated :
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
at System.Data.SqlClient.SqlDataReader.get_MetaData()
So, to create test data, you could, following Vinod's suggestion, switch the delete rule to ignore, add your root organisation, and switch the delete rule back to protect, or you could create scaffolding screens to edit your data without tampering with the delete rule.
Dorine