Hi,

I can't understand at all, about how set/drop default update the system
tables against doing an alter domain of the related field which I want
to change. (I'm looking into RDB$RELATION_FIELDS)

Using:
ALTER TABLE MY_TABLE ALTER COLUMN MY_FIELD SET DEFAULT 'X'

The RDB$RELATION_FIELDS table update RDB$DEFAULT_VALUE and RDB
$DEFAULT_SOURCE.

(Idem if I do a DROP DEFAULT)

BTW, over a existent filed, if I want to change the default value I can
do ALTER DOMAIN RDB$xxx SET/DROP DEFAULT, but the RDB$RELATION_FIELDS
doesn't change the same fields like ALTER TABLE... does.

Notice what ALTER TABLE MY_TABLE ALTER COLUMN MY_FIELD DROP DEFAULT
statement raise an error if there isn't a default specification on
MY_FIELD and ALTER DOMAIN... doesn't.

Then, the question is, what is the correct approach for use SET/DROP
default?
Can I use either one or the other indifferently?

I hope I was clear.
Thanks in advance.
---
Maxi.