Daniel,

>The proper way to change it is to create a temp field with the desired
>properties...

I am puzzled.

There is a politically correct way to change a field attribute ?

When doing it, can one dress causally or is a necktie de-rigour ? :)

If fields attributes are stored in RDB$RELATION_FIELDS, I expect to get
logic results when I change the table.

Can you quote public documents that advice against touching system tables ?

For what I know, Interbase WorkBench, Marathon and surely QuickDesk: all
these tools routinely change fields in system tables in order to get quick
results.

Of course if you want to suggest a method that will work when compared to a
method that does not work, I take that you are confirming a bug in FB ...

Thank you

Duilio