Oracle Database Discussions

Hi experts;

I have a table T (i varchar(5), j varchar(5));
This table has two indexes basis function

Create index id1 on T(lower(i));
Create index id2 on T(lower(j));

Select * from T
where
lower(i)='a'
or
lower(j)='a';

this query has not the same explain plan on a Enterprise version or a Standard Edition.
On the enterprise, Oracle make an "bitmap transformation" and use the both indexes.

With a standard Edition, Oracle make a full scan of the table.
I know bitmap index are only available on Enterprise, but I don't kwow if this the same for "Bitmap transformation".

Thanks for you help !

Laurent;