Currently, it is not possible to create a view in one database sourced from a collection in another database. As mentioned in db.createView()  documentation, the `source` parameter for the view does not include the database name and implies the same database as the view to create. It is implicitly assumed (and in fact, required), that the source collection must be in the same database as the view being collected.

This is a feature-improvement request, to allow for creating a view in one database sourced from a collection in another database.