I'm using IBExpert and it allows me to change the type of a field
freely, but its changes are made directly to system tables.

For example, i have a field of type varchar(25), and i want to change
it's type to a previously create domain, PS_CODIGO, of type varchar(50).

After the change in the GUI, it runs the following script:

update RDB$RELATION_FIELDS set
RDB$FIELD_SOURCE = 'PS_CODIGO'
where (RDB$FIELD_NAME = 'CODIGO') and
(RDB$RELATION_NAME = 'V2$CEC1')
;

So far, so good. But this change doesn't smells good to me, as i have
some indices in that field and it's also used inside some stored
procedures and/or triggers.

I'd like to know if i can have troubles with this sort of
modification, and what kind of troubles should i expect.

Regards,

Fabiano.