Hi Tania,
I've been using external tables with Oracle, SqlServer & MySql.
And I have wishes:
https://www.outsystems.com/ideas/6578/use-integration-studio-to-generate-actions-on-oracle-procedures-functions-and-pa
https://www.outsystems.com/ideas/7347/using-wallet-for-external-database-connection-to-oracle-cloud-database