If I get your question correctly, you are seeing the box for Database, but it's not being identified as Oracle, right? Like the image below.
When Dynatrace is unable to identify the database type, it will show up as a generic "Database". The reason this can happen is if the application uses a database provider that is not standard, it hasn't been implemented on our code. For the standard JDBC and ADO.NET it should show up correctly.
You could open a support case to confirm if there's an issue of if it's indeed an unsupported database provider.