Liselotte, here are some things to consider:

1. Error with Existing Row Filters: If a row filter is applied to an existing table, and you attempt to execute a CREATE TABLE IF NOT EXISTS statement, it may lead to failure because row filters impose dynamic constraints that can cause configuration inconsistencies. To avoid such errors, explicitly check and handle the existence of row filters before performing creation operations.
2. Modifying a Table with Row Filters: If you encounter issues where a table becomes inaccessible due to orphaned row filter references, you can remove the row filters using the ALTER TABLE <table_name> DROP ROW FILTER; command before making further modifications.
3. Best Practices for External Tables:

   • Avoid overlapping storage paths among external tables and volumes, as this is not supported in Unity Catalog and will throw path overlap errors.
   • Use a flat hierarchical structure for external tables and register them at sub-directory levels under external locations for clean organization and governance.
4. Unity Catalog Table Constraints:

   • For external tables, ensure the location associated with the table is not intersecting with managed paths or other external paths to avoid errors.
   • Always verify that the external storage credential has appropriate permissions (e.g., read/write access) and is configured correctly.