Primary key or composite key?

Question

hi all,

In my application i have to collect information from the resume and create a userid and password for the resume.

I want to create a uname,pwd once for the resume.

normally i create primary key for uname. but two data should not be the same with two different user ids..

So i decided to create composite key. which one is better primary key or composite keys or both...

how far it is useful

Guide me

Thanks in advance

Answer 1

Primary key