DBU Problem: F1-KEY command doesn't work on DB file

Hi Mapics group:

I am trying to edit an inhouse created DB file using DBU.

When I bring up the file and try to go to a specific record using the F1-KEY 
command, I get an error message, "Function key not allowed."

The DBU help screen for that command says:

"CMD 1-KEY.  Allows a starting key selection on logical or keyed physical 
files.  If the file has a single record format, the current key is displayed.  
Partial keys may be used.  Not valid for non-keyed physical files."

What is the difference between a "keyed" and "non-keyed" DB file?

When we create inhouse DB files using Query/400, is the resulting file 
automatically a "non-keyed" DB file?

Is there any way to convert a "non-keyed" DB file into a "keyed" DB file?  If 
there isn't a way to do this, I do I use DBU to go directly to a specific 
record on a very large DB file?

I look forward to your good assistance on this matter.

Regards,
Al Gershen
Grants Pass, OR
aldg@mail.rvi.net
Aldg's Photos at:
http://communities.msn.com/AldgsPhotos/