Mapping a extension of a external Database

Hello Everyone,

I have the following question:
I'm connected to an external (Oracle) database. Through an extension I have access to this tables and views. 
When I want to access any of this entities I need to reference directly to the extension. With this reference I indirectly give also permission to use the CRUD operation of this entities (because I cannot set the read only option). 
My thought was to map the entities of this extension to my own entities, is this the best way to do so? How does the 4 Layer Architecture handle this?

You basically use the Oracle database entities just like you would your own entities.
The problem with this is that every module will get the permission to use the standard create, update delete actions (because you reference to the extension). I want to change this actions (make my own actions, for example log all action's to another entity). 

When you create your own entities you have the possibility to set it to public-->yes BUT enable expose read only.Then your other modules will not get the actions to do any changes to the entity.

The same I want for my entities that come from the extension.
Then you can create another eSpace that contains your tables which you can expose to others as read-only. You'll have to write the interface to expose that data and sync it back with Oracle
Oké Thanks Gerry!