Re: instance_name as unprivileged user

according to the 9i docs this

select sys_context('USERENV','DB_NAME') FROM DUAL

should work, and it actually does.

You could also in PL/sql use

declare
str_len number;
str varchar2(30);
begin
dbms_utility.get_parameter_value('db_name', str_len, str); end;
/
or select * from global_name

etc, etc,etc

Hth

-- 
Sybrand Bakker
Senior Oracle DBA