Re: BUG #1162: lots of values that have "unique" property

On Sun, 13 Jun 2004, PostgreSQL Bugs List wrote:

>
> The following bug has been logged online:
>
> Bug reference:      1162
> Logged by:          Fehmi Noyan ISI
>
> Email address:      fnoyan@linuxmail.org
>
> PostgreSQL version: 7.4
>
> Operating system:   FreeBSD 5.1 - x86 platform
>
> Description:        lots of values that have "unique" property
>
> Details:
>
> Hello
>  First of all I am not a database expert! I just run MySQL and PostgreSQL
> on my FreeBSD 5.1 system and develop small web applications.
>  I am new to PostgreSQL and don't know this is a bug (or something like
> it) or not. But while I was reading the constraints section of user's
> manual I noticed something strange!
>  Please consider the procedure below...
>
>  noyan=> CREATE TABLE table_1 (
>  noyan(> id integer UNIQUE NOT NULL,
>  noyan(> dsc text NOT NULL,
>  noyan(> passwd text NOT NULL);
>
> The table is created successfully.Ok, go on...
>
>  noyan=> INSERT INTO table_1 VALUES (1,'System Admin','something');
>  noyan=> INSERT INTO table_1 VALUES (1,'Normal User','something');
>  ERROR:  Cannot insert a duplicate key into unique index table_1_id_key
>  noyan=> SELECT * FROM table_1;
>   id |     dsc      |  passwd
>  ----+--------------+-----------
>    1 | System Admin | something
>  (1 row)
>
>  I got the error message as expected. Everything is ok.Now, let's create
> another table called "table_2" with an inheritence from "table_1".
>
>  noyan=> CREATE TABLE table_2 (ext_column integer) INHERITS (table_1);

Primary key, unique and foreign key constraints are not currently
inherited by child tables.  This is a known deficiency with the
inheritance system, but AFAIK isn't being actively worked on by anyone at
this time.