> I just tried to remove the "not null" constraint on one of my columns,
> but the generated SQL is buggy:
> UPDATE RDB$RELATION_FIELDS SET RDB$NULL_FLAG = NULL
> WHERE RDB$FIELD_NAME = '"ColumnName"' AND RDB$RELATION_NAME = 'MyTable';
which FR version is that? I just tried with SVN revision 2242, and it works there.
Note that SVN revision 2210 has a bug fix with the comment
* Fix bug reported 2011-08-11 by Kjell Rilbe on dev list:
"SQL generation bug for nullability change"