Re: Catalog domain not-null constraints

On 09.04.24 10:44, jian he wrote:
>> 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.)

> in ruleutils.c
> /* conkey is null for domain not-null constraints */
> appendStringInfoString(&buf, "NOT NULL VALUE");
> 
> should be
> 
> /* conkey is null for domain not-null constraints */
> appendStringInfoString(&buf, "NOT NULL ");

Good catch, fixed.

> currently
> src6=# \dD connotnull
> /******** QUERY *********/
> SELECT n.nspname as "Schema",
>         t.typname as "Name",
>         pg_catalog.format_type(t.typbasetype, t.typtypmod) as "Type",
>         (SELECT c.collname FROM pg_catalog.pg_collation c, pg_catalog.pg_type bt
>          WHERE c.oid = t.typcollation AND bt.oid = t.typbasetype AND
> t.typcollation <> bt.typcollation) as "Collation",
>         CASE WHEN t.typnotnull THEN 'not null' END as "Nullable",
>         t.typdefault as "Default",
>         pg_catalog.array_to_string(ARRAY(
>           SELECT pg_catalog.pg_get_constraintdef(r.oid, true) FROM
> pg_catalog.pg_constraint r WHERE t.oid = r.contypid
>         ), ' ') as "Check"
> FROM pg_catalog.pg_type t
>       LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
> WHERE t.typtype = 'd'
>    AND t.typname OPERATOR(pg_catalog.~) '^(connotnull)$' COLLATE
> pg_catalog.default
>    AND pg_catalog.pg_type_is_visible(t.oid)
> ORDER BY 1, 2;
> /************************/
> 
> ---
> Since the last column is already named as "Check", maybe we need to
> change the query to
>         pg_catalog.array_to_string(ARRAY(
>           SELECT pg_catalog.pg_get_constraintdef(r.oid, true) FROM
> pg_catalog.pg_constraint r WHERE t.oid = r.contypid
>           and r.contype = 'c'
>         ), ' ') as "Check"
> 
> That means domain can be associated with check constraint and not-null
> constraint.

Yes, I changed it like you wrote.

> the url link destination is fine, but the url rendered name is "per
> the section called “Notes”" which seems strange,
> please see attached.

Hmm, changing that would be an independent project.

I have committed the patch with the two amendments you provided.

I had also added a test of \dD and that caused some test output 
instability, so I added a ORDER BY r.conname to the \dD query.