Linking to SQL Server / Oracle – don’t skip the set key field on linking

After writing Update queries with multiple joins on linked Oracle Databases I was receiving an error on running particular update queries on linked tables that had no Primary Key identified.
On linking the tables I had been asked to identify a field with a unique value. Not thinking I had passed on this and initially this didn’t seem to be an issue. Subsequently I identified that the error associated with the update queries originated from this lack of key identification. Re-linking required tables and ensuring that I identified a unique key allowed for these queries to be processed. This of course is because Access is wanting to use the unique key to identify the field for update.

The message

Operation must use an updateable query.

Just one to be mindful of if you are linking to enterprise grade backend databases.