Because rowids identify the location of a row, they are the fastest way to retrieve a row from a database. Hence,
indexes store rowids for the indexed values.
Selecting rowids from a table
rowid is also a
pseudo column which evaluates to a selected record's rowid:
create table tq84_rowid (
id number,
col_1 varchar2(20)
);
insert into tq84_rowid values(1, 'foo');
insert into tq84_rowid values(2, 'bar');
insert into tq84_rowid values(3, 'baz');
select
rowid
r.*
from
tq84_rowid r;
drop table tq84_rowid;