Oracle: NLS_SORT=GENERIC_BASELETTER

create table tq84_names (
    id   integer,
    name nvarchar2(10)
);

begin
   insert into tq84_names values ( 1, 'Jérôme'  );
   insert into tq84_names values ( 2, 'Zoë'     );
   insert into tq84_names values ( 3, 'François');
   insert into tq84_names values ( 4, 'René'    );
   insert into tq84_names values ( 5, 'Šárka'   );
   insert into tq84_names values ( 6, 'Błażej'  );
   insert into tq84_names values ( 7, 'Željko'  );
   commit;
end;
/

select * from tq84_names where name = 'Rene';
--
-- No record found

alter session set nls_comp = linguistic;
alter session set nls_sort = generic_baseletter;
select * from tq84_names where name = 'Rene';
--
-- 4  René

create index tq84_names_ix_1 on tq84_names (name);
explain plan for select * from tq84_names where name = 'Rene';
select * from dbms_xplan.display(format=>'basic');
-- ----------------------------------------
-- | Id  | Operation         | Name       |
-- ----------------------------------------
-- |   0 | SELECT STATEMENT  |            |
-- |   1 |  TABLE ACCESS FULL| TQ84_NAMES |
-- ----------------------------------------

create index tq84_names_ix_2 on tq84_names (nlssort(name, 'nls_sort=generic_baseletter'));


explain plan for select * from tq84_names where name = 'Rene';
select * from dbms_xplan.display(format=>'basic');
-- -------------------------------------------------------
-- | Id  | Operation                   | Name            |
-- -------------------------------------------------------
-- |   0 | SELECT STATEMENT            |                 |
-- |   1 |  TABLE ACCESS BY INDEX ROWID| TQ84_NAMES      |
-- |   2 |   INDEX RANGE SCAN          | TQ84_NAMES_IX_2 |
-- -------------------------------------------------------

drop table tq84_names purge;