How to set up a table where 2 columns together must be unique?

-----Original Message-----
From: Scott Chapman [mailto:scott_list@mischko.com]
Sent: Friday, October 31, 2003 10:04 PM
To: pgsql-general@postgresql.org
Subject: [GENERAL] How to set up a table where 2 columns
together must be unique?

Hi all!

I want to create a table:

user_id: bigserial
user_name: text
user_company: text
password: text

How do I build this table so that user_name+user_company must
be unique? This way there can be only one of a given username
for a given company name
but there can be more than one of a given username if they
are with different
companies.

Put a unique index on user_name, user_company.