Horton

Re: Catalog domain not-null constraints

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: jian he <jian.universality@gmail.com>, Aleksander Alekseev <aleksander@timescale.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Alvaro Herrera <alvherre@alvh.no-ip.org>, vignesh C <vignesh21@gmail.com>
Date: 2024-04-08T09:53:40Z
Lists: pgsql-hackers

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  1. Fix ALTER DOMAIN NOT NULL syntax

  2. Catalog domain not-null constraints

  3. Add tests for domain-related information schema views

Attachments

On 21.03.24 12:23, Peter Eisentraut wrote:
>> All the examples in the tests append "value" to this, presumably by
>> analogy with CHECK constraints, but it looks as though anything works,
>> and is simply ignored:
>>
>> ALTER DOMAIN d ADD CONSTRAINT nn NOT NULL xxx; -- works
>>
>> That doesn't seem particularly satisfactory. I think it should not
>> require (and reject) a column name after "NOT NULL".
> 
> Hmm.  CREATE DOMAIN uses column constraint syntax, but ALTER DOMAIN uses 
> table constraint syntax.  As long as you are only dealing with CHECK 
> constraints, there is no difference, but it shows up when using NOT NULL 
> constraint syntax.  I agree that this is unsatisfactory.  Attached is a 
> patch to try to sort this out.

After studying this a bit more, I think moving forward in this direction 
is the best way.  Attached is a new patch version, mainly with a more 
elaborate commit message.  This patch makes the not-null constraint 
syntax consistent between CREATE DOMAIN and ALTER DOMAIN, and also makes 
the respective documentation correct.

(Note that, as I show in the commit message, commit e5da0fe3c22 had in 
passing fixed a couple of bugs in CREATE and ALTER DOMAIN, so just 
reverting that commit wouldn't be a complete solution.)