31.03.2015 07:20, Adriano dos Santos Fernandes wrote:
>
> Currently there is inconsistencies in fields [NOT] NULL flag on its
> (field) flag does not matches the domain.
>
> Use CONNECT or CREATE DATABASE to specify a database
> SQL> create database 'z.fdb';
> SQL> create domain d1n integer not null;
> SQL> create table t1 (n1 d1n);
> SQL>
> SQL> insert into t1 values (null); -- ok
> Statement failed, SQLSTATE = 23000
> validation error for column "T1"."N1", value "*** null ***"
> SQL>
> SQL> alter table t1 alter n1 null;
> SQL>
> SQL> show table t1;
> N1 (D1N) INTEGER Not Null
> SQL>
> SQL> insert into t1 values (null);
Before discussing the problem, I think we should change the syntax. The
SQL spec suggests ALTER [COLUMN] N1 {SET | DROP} NOT NULL instead of our
current ALTER [COLUMN] N1 [NOT] NULL. And I like this, as formally NOT
NULL is a constraint. BTW, we seem to miss a DDL ability to change the
column-level CHECK constraint.
With SET NOT NULL and DROP NOT NULL, we don't just set the field flag
but explicitly declare that we want a constraint or we don't want a
constraint. So even if a constraint was inherited from a domain, I think
this should mean to change the constraint. In other words, the engine is
correct in treating the new definition as an override.
Dmitry
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