Do I need DME or ADF in an IFR-certified GPS panel?

Newps wrote:

Not required. You just need to have any fix of the approach in the
database.

Usually I agree with you, but I am confused here.

Why WOULDN'T you need the physical location of the DME in the database,
if you are using the distance from that location as the basis of
whatever decision you were using the DME for?

I know that your answers are always light on the "why" part of the
answer, but just once do you think you can throw the why in? as well as
a reference, because I am unfamiliar with the rationale for your answer.

Dave