Others have already helped you solve your problem. I thought I could
just say why your original statement didn't work (or at least one of the
reasons, I haven't tested anything).

> select CURRENT_TIMESTAMP into NEW.MYTIMESTAMPFIELD,
> from rdb$database;

The syntax isn't

SELECT ... INTO ... FROM

Rather, it is

SELECT ... FROM ... INTO

So, I'd expect

select CURRENT_TIMESTAMP from rdb$database
into NEW.MYTIMESTAMPFIELD

to not produce any syntactical error.

Set