Horton

Re: PostgreSQL domains and NOT NULL constraint

Vik Fearing <vik@postgresfriends.org>

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From: Vik Fearing <vik@postgresfriends.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Erki Eessaar <erki.eessaar@taltech.ee>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2023-10-14T14:00:49Z
Lists: pgsql-hackers 
On 10/13/23 06:37, Tom Lane wrote:
> If it's not nominally of a domain type, please cite chapter and
> verse that says it isn't.

Okay, I found it.


SQL:2023-2 6.7 <column reference>

Syntax Rules

5) Let C be the column that is referenced by CR. The declared type of CR is
    Case:
    a) If the column descriptor of C includes a data type, then that 
data type.

    b) Otherwise, the data type identified in the domain descriptor that 
describes the domain that is identified by the <domain name> that is 
included in the column descriptor of C.


So the domain should not be carried into a query expression (including 
views) and the data type should be the one specified in the domain.
-- 
Vik Fearing