在SQL Server 2008中，尾部空格作为主键的Varchar

Is it possible to have a varchar column as a primary key with values like 'a ' and 'a', is gives always this error "Violation of PRIMARY KEY constraint" in MS SQL Server 2008. In Oracle dons't give any error. BTW I'm not implementing this way I'm only trying to migrate the data from oracle to sql server.Is it possible to have a varchar column as a pr