oracle 8i
Give you a SYS_CONTEXT function that give you access to the value of a lot of user environment variables.
eg. DB_NAME, IP_ADDRESS, TERMINAL, SESSION_ID...
The sql to get the DB_NAME is
select sys_context('USERENV','DB_NAME') from dual;

before oracle 8i,
you can connect as sys and create a view for use
create view DB_NAME_V as select name from v$database;
create public synonym DB_NAME_V for DB_NAME_V;
grant select on DB_NAME_V to public;

The value for GLOBAL_NAME on 8i or 7.3.x will depend on the INIT.ORA of yr ddatabase and also depend if someone has changed.

Check what is it about "global name" from metalink

Doc ID : 115499.1


Hope it is helpful to you.