Re: primary key question

>From: Carolyn Lu Wong <carolyn@kss.net.au>
>To: "pgsql-sql@postgresql.org" <pgsql-sql@postgresql.org>
>Subject: [SQL] primary key question
>Date: Thu, 20 Jul 2000 17:26:30 +1000
>
>create table aaa(
>    field1    .... not null,
>    field2  ....,
>    ....,
>    primary key (field1, field2)
>);
>
>Based on the above table definition, field2 allows null values. But
>after the table created based on the above script, field2 becomes not
>null. The only conclusion I come up with is setting the field as part of
>the primary key, PostgreSQL automatically sets the field to not null. Or
>is it something else?
>
>Is this a feature or bug?

Sure it is a feature , since the first integrity rule force the primary 
key(s) to be not null automatically whether entirely or partially.



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