Once you have created your extension (A set of Actions, Entities, and Structures available in Service Studio but implemented in foreign technologies), simply define the entities exported by the extension. These entities allow you to use database tables that exist outside OutSystems Platform.
To publish a new extension that contains entities, your OutSystems Platform user must have the Allow External Entities permission. Check with the Service Center administrator for a list of your permissions .
To add an entity to your extension, simply execute one of the following operations:
Add the entity manually to the extension. How?
Import the entity definition from a database, through the Import Entities from Database wizard.
Add an Entity | Import Entities from Database | Entity Editor | About an Extension