Subject [IBDI] DEFAULT Values
Author Dmitry Yemanov

As far as I understand, I cannot change DEFAULT value of the existing
column. 'ALTER TABLE table_name ALTER COLUMN column_name' statement does not
allow SET DEFAULT syntax, although it is defined by the SQL 92
specification. 'ALTER DOMAIN domain_name SET DEFAULT' statement changes
default value for the given domain, but does not affect the existing columns
based on this domain.

If I'm wrong, please point me what I'm missing. Otherwise, maybe we need
something to add/change there. Any thoughts?