Submitted by: @WarmBooter

Votes: 2

Firebird does not allow changing the field type when there are pks, fks, indexes, in that field. This is a known limitation and a real pain.
But I can't see why it doesn't allow changing to a domain with the same type, ie:
Field was created as integer not null, and you want to change it to an existing domain, which is also declared as integer not null.
In this case, there is no change to the underlying stored data, so why do not allow it?