Case Sencitivity ASA12

Hi
I have my db without case Sensitivity option.
And my example:

create table test (desc varchar(5));

insert into desc values (‘a’);
insert into desc values (‘A’);

Result of sql: select * from test
where desc = ‘A’
is:
a
A

I would like to have only ‘A’.
Is it possible to change db option without generate a new db.

Regards