BUG #1662: Table constrains are not properly inherited.

The following bug has been logged online:

Bug reference:      1662
Logged by:          Steven Mooij
Email address:      steven@mooij.org
PostgreSQL version: 7.4.7
Operating system:   i386-pc-linux-gnu, compiled by GCC i386-linux-gcc (GCC)
3.3.5 (Debian 1:3.3.5-12)
Description:        Table constrains are not properly inherited.
Details:

When a table is inherited from, it's table constraints are 'disabled':

CREATE TABLE super (x INTEGER, PRIMARY KEY (x));
CREATE TABLE sub (y INTEGER) INHERITS (super);
INSERT INTO sub VALUES (1, 1);
INSERT INTO sub VALUES (1, 2);
INSERT INTO super VALUES (1);

This should result in a 'duplicate key violation' for the unique constraint
on super(x), but it doesn't.

In this case

SELECT x FROM super;

results in:

 x
---
 1
 1
 1
(3 rows)