Hey! So you're thinking about creating an Iceberg table as an external table on Unity Catalog? Yeah, there are definitely some limitations to keep in mind—especially around writes and creation, since it's still in preview.

he main thing is: you can read Iceberg tables from other engines through UC external tables, but you can't write to them that way. Write access is only available for managed tables right now. Check out the https://docs.databricks.com/aws/en/external-access/iceberg#requirements

So you can read Iceberg table from other engines, but can't write vía UC using external tables, only available for managed tables.

That said, if you're already creating Iceberg tables in another engine, you can still access them through UC using LHF (Lakehouse Federation). That way you can read them without hitting those external table write limitations. https://docs.databricks.com/aws/en/iceberg/#read-iceberg-tables-managed-by-other-catalogs

Hope that helps!