Sorry but this is still not clear
What do you mean by "register the database schema of applications registered in MEGA"?
If you mean modelling data models? you can do that with Data Model, Entity objects and etc. if you want exactly SQL database modelling you can use the Database and Table objects in mega
If I understand and are definitely using HOPEX with SQL Storage (SQL server, Oracle)
1) You want to ist of tables used
2) Maybe you also want to access (consultation, update) the tables from an external application
Let us go further
1) There is no document that list these tables.
As said before in this thread, we do not provide documentation regarding our implementation in SQL databases
If you want to have a good idea of the data model, it is wised to list and browse the Metaclasses using HOPEX common tools (query, explorer, metamodel diagrams..)
2) Consultation and update can be performed using the standard end user interface or the API script
Regarding consultation and update from an external application
Excuse me for saying so, but you are not expressing yourself very clearly.
But from what I can understand from the thread, you would like to document tables of a database associated with an application that you have created in Hopex.
In order to do so, you would need the Database Builder module, which manages the conceptual, logical and physical level of a database.