Asking for name/password and connecting

Dear Sirs:

I know it must be a silly and common question, but I haven't found the
answer looking in the archives.

Situation:
-  I have Access 2000 as front-end (with linked tables), PostgreSQL 8.1
as back-end, using ODBC.
-  I need that the user could enter his name and password (instead of
saving it on the system DNS).

Question:
-  Do I have to ask the user for the name/password and later relink
programatically all the tables? or is there a better way?


Thank you for your help