BUG #5064: not-null constraints is not inherited

The following bug has been logged online:

Bug reference:      5064
Logged by:          Tomonari Katsumata
Email address:      katsumata.tomonari@oss.ntt.co.jp
PostgreSQL version: 8.5dev, 8.4.1
Operating system:   Windows XP, RHEL 5.2
Description:        not-null constraints is not inherited
Details:

Hi,

I found a bug about inheritance.
The user manual says, "All check constraints and not-null constraints on a
parent table are automatically inherited by its children."
But, the behavier is not true. The sample is like below.

postgres=# CREATE TABLE parent (id integer);
postgres=# CREATE TABLE child () inherits (parent);
postgres=# ALTER TABLE parent ADD PRIMARY KEY (id);
postgres=# \d+ parent
                Table "public.parent"
 Column |  Type   | Modifiers | Storage | Description
--------+---------+-----------+---------+-------------
 id     | integer | not null  | plain   |
Indexes:
    "parent_pkey" PRIMARY KEY, btree (id)
Child tables: child
Has OIDs: no

postgres=# \d+ child
                 Table "public.child"
 Column |  Type   | Modifiers | Storage | Description
--------+---------+-----------+---------+-------------
 id     | integer | 　        | plain   |
Inherits: parent
Has OIDs: no

child table does not have a "not null" constraints.
I think it's not desirable behavier.

On the other hand, if I set a constraints using
"ALTER COLUMN SET NOT NULL", the constraints is inherited by its child.

postgres=# DROP TABLE parent, child;
postgres=# CREATE TABLE parent (id integer);
postgres=# CREATE TABLE child () inherits (parent);
postgres=# ALTER TABLE parent ALTER COLUMN id SET NOT NULL;
postgres=# \d+ parent
                Table "public.parent"
 Column |  Type   | Modifiers | Storage | Description
--------+---------+-----------+---------+-------------
 id     | integer | not null  | plain   |
Child tables: child
Has OIDs: no

postgres=# \d+ child
                 Table "public.child"
 Column |  Type   | Modifiers | Storage | Description
--------+---------+-----------+---------+-------------
 id     | integer | not null  | plain   |
Inherits: parent
Has OIDs: no



regards,
--
Tomonari Katsumata
katsumata.tomonari@oss.ntt.co.jp