How to link a login to a database user

From: Krygim (
Date: 05/12/04

Date: Wed, 12 May 2004 23:05:57 +0800

USER1 is the db_owner of the database INVENTORY. There exists an identical
SQL Server login name USER1. When I double-click on the login name, in the
Database Access page, I find that USER1 is permitted to access INVENTORY.
However, there is no linkage between the login USER1 and database owner
USER1. The "User" cell at the right of the INVENTORY database is blank in
the Database Access page. However when I try to enter USER1 into the cell, I
get an error message telling me the user USER1 already exists in INVENTORY.

However can I link the login name to the database user name?