From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thiemo Kellner <thiemo@gelassene-pferde.biz>
cc: pgsql-general@lists.postgresql.org
Subject: Re: Is this a buggy behavior?
In-reply-to: <51eb3063-1d90-40c6-a8c6-9a77fe105a61@gelassene-pferde.biz>
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Comments: In-reply-to Thiemo Kellner <thiemo@gelassene-pferde.biz>
	message dated "Sun, 24 Mar 2024 15:59:46 +0100"
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Date: Sun, 24 Mar 2024 11:17:11 -0400
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Thiemo Kellner <thiemo@gelassene-pferde.biz> writes:
> Am 24.03.2024 um 15:54 schrieb Erik Wienhold:
>> This is required by the SQL standard: columns of a primary key must be
>> NOT NULL.  Postgres automatically adds the missing NOT NULL constraints
>> when defining a primary key.  You can verify that with \d test1 in psql.

> To me, this behaviour, while correct, is not too concise. I wished, that 
> PG issued a warning about a definition conflict. In PostgreSQL, a PK 
> must always be not nullable, so explicitly defining on of a PK's columns 
> as nullable is contradictory, one should get notified of.

To do that, we'd have to remember that you'd said NULL, which we
don't: the word is just discarded as a noise clause.  Considering
that this usage of NULL isn't even permitted by the SQL standard,
that seems like a bit too much work.

			regards, tom lane