select * from lpeduc.com_groupby;
GROUPBY_NAME
--------------------
Brand
Manufacturer
Sub Segment
Super Segment

insert into lpeduc.com_groupby values('Detroit');
1 row created.

SQL> select * from lpeduc.com_groupby;

GROUPBY_NAME
--------------------
Brand
Detroit
Manufacturer
Sub Segment
Super Segment

SQL> desc lpeduc.com_groupby
Name Null? Type
----------------------------------------- -------- ----------------------------
GROUPBY_NAME NOT NULL VARCHAR2(20)

This has a primary key index on GROUPBY_NAME.

Let me know if someone find something???.