SQL & PL/SQL

normally, an Select.....Into.... statement has a row reference or even a number entered into a location (another row reference or a form field).

However, I'm trying to put in a character such as the letter E for example into a form field.....looking like this:

Select 'E' Into fieldname From Dual
Where fieldname2 = 'D';

Basically, I want it so that whenever fieldname2 has a D entered that it will automatically put an E into fieldname. Now this code seems to work, and yet I get errors from my form editor (Centura) saying "Symbol undefined or unable to reference from fieldname2" as well as a failed value error on the script program (Worktech)....and then after it gives back those errors, it runs as planned putting an E into fieldname when D is in fieldname2. If I try to suppress those errors, it wont do it at all.

Is there a way around this to make it work or perhaps a different code to do the same thing?