You can’t.
EDIT:
If your use case is being able to run SQL queries to truncate tables, this is absolutely possible. It can be done via the Java Core API Mendix exposes. You can utilize it by creating a Java action which has an input SQL string parameter:
Be aware that this is a tricky thing, because of two specifics of the Mendix database:
What do you want to achieve?
Your Mendix application has its own database, which will be managed under the hood. In your app can you manage your domain models, but Mendix translates those to its own table structure. There are also a lot of extra Mendix tables, which are not visible in the modeller. In my opinion there is no need to view.