How to build a funciton to return primary key,alternate key and foreign key fields

Hi every body. I need to create a function to return a string containing :

A) primary key fields together with primary key names .
B)alternate key fields together with correspondingly alternate key names.
c)foreign key fields together with correspondingly foreign key names.

I be happy if some one show me how to build such funciton since i never refrenced reletionship keys via vba.Thanks